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     42  1.1  mrg <h1 class="settitle">Installing GCC: Configuration</h1>
     43  1.1  mrg <a name="index-Configuration-1"></a><a name="index-Installing-GCC_003a-Configuration-2"></a>
     44  1.1  mrg Like most GNU software, GCC must be configured before it can be built. 
     45  1.1  mrg This document describes the recommended configuration procedure
     46  1.1  mrg for both native and cross targets.
     47  1.1  mrg 
     48  1.1  mrg    <p>We use <var>srcdir</var> to refer to the toplevel source directory for
     49  1.1  mrg GCC; we use <var>objdir</var> to refer to the toplevel build/object directory.
     50  1.1  mrg 
     51  1.1  mrg    <p>If you obtained the sources via SVN, <var>srcdir</var> must refer to the top
     52  1.1  mrg <samp><span class="file">gcc</span></samp> directory, the one where the <samp><span class="file">MAINTAINERS</span></samp> file can be
     53  1.1  mrg found, and not its <samp><span class="file">gcc</span></samp> subdirectory, otherwise the build will fail.
     54  1.1  mrg 
     55  1.1  mrg    <p>If either <var>srcdir</var> or <var>objdir</var> is located on an automounted NFS
     56  1.1  mrg file system, the shell's built-in <samp><span class="command">pwd</span></samp> command will return
     57  1.1  mrg temporary pathnames.  Using these can lead to various sorts of build
     58  1.1  mrg problems.  To avoid this issue, set the <samp><span class="env">PWDCMD</span></samp> environment
     59  1.1  mrg variable to an automounter-aware <samp><span class="command">pwd</span></samp> command, e.g.,
     60  1.1  mrg <samp><span class="command">pawd</span></samp> or &lsquo;<samp><span class="samp">amq -w</span></samp>&rsquo;, during the configuration and build
     61  1.1  mrg phases.
     62  1.1  mrg 
     63  1.1  mrg    <p>First, we <strong>highly</strong> recommend that GCC be built into a
     64  1.1  mrg separate directory from the sources which does <strong>not</strong> reside
     65  1.1  mrg within the source tree.  This is how we generally build GCC; building
     66  1.1  mrg where <var>srcdir</var> == <var>objdir</var> should still work, but doesn't
     67  1.1  mrg get extensive testing; building where <var>objdir</var> is a subdirectory
     68  1.1  mrg of <var>srcdir</var> is unsupported.
     69  1.1  mrg 
     70  1.1  mrg    <p>If you have previously built GCC in the same directory for a
     71  1.1  mrg different target machine, do &lsquo;<samp><span class="samp">make distclean</span></samp>&rsquo; to delete all files
     72  1.1  mrg that might be invalid.  One of the files this deletes is <samp><span class="file">Makefile</span></samp>;
     73  1.1  mrg if &lsquo;<samp><span class="samp">make distclean</span></samp>&rsquo; complains that <samp><span class="file">Makefile</span></samp> does not exist
     74  1.1  mrg or issues a message like &ldquo;don't know how to make distclean&rdquo; it probably
     75  1.1  mrg means that the directory is already suitably clean.  However, with the
     76  1.1  mrg recommended method of building in a separate <var>objdir</var>, you should
     77  1.1  mrg simply use a different <var>objdir</var> for each target.
     78  1.1  mrg 
     79  1.1  mrg    <p>Second, when configuring a native system, either <samp><span class="command">cc</span></samp> or
     80  1.1  mrg <samp><span class="command">gcc</span></samp> must be in your path or you must set <samp><span class="env">CC</span></samp> in
     81  1.1  mrg your environment before running configure.  Otherwise the configuration
     82  1.1  mrg scripts may fail.
     83  1.1  mrg 
     84  1.1  mrg    <p>To configure GCC:
     85  1.1  mrg 
     86  1.3  mrg <pre class="smallexample">     % mkdir <var>objdir</var>
     87  1.3  mrg      % cd <var>objdir</var>
     88  1.3  mrg      % <var>srcdir</var>/configure [<var>options</var>] [<var>target</var>]
     89  1.1  mrg </pre>
     90  1.1  mrg    <h3 class="heading"><a name="TOC0"></a>Distributor options</h3>
     91  1.1  mrg 
     92  1.1  mrg <p>If you will be distributing binary versions of GCC, with modifications
     93  1.1  mrg to the source code, you should use the options described in this
     94  1.1  mrg section to make clear that your version contains modifications.
     95  1.1  mrg 
     96  1.1  mrg      <dl>
     97  1.1  mrg <dt><code>--with-pkgversion=</code><var>version</var><dd>Specify a string that identifies your package.  You may wish
     98  1.1  mrg to include a build number or build date.  This version string will be
     99  1.1  mrg included in the output of <samp><span class="command">gcc --version</span></samp>.  This suffix does
    100  1.1  mrg not replace the default version string, only the &lsquo;<samp><span class="samp">GCC</span></samp>&rsquo; part.
    101  1.1  mrg 
    102  1.1  mrg      <p>The default value is &lsquo;<samp><span class="samp">GCC</span></samp>&rsquo;.
    103  1.1  mrg 
    104  1.1  mrg      <br><dt><code>--with-bugurl=</code><var>url</var><dd>Specify the URL that users should visit if they wish to report a bug. 
    105  1.1  mrg You are of course welcome to forward bugs reported to you to the FSF,
    106  1.1  mrg if you determine that they are not bugs in your modifications.
    107  1.1  mrg 
    108  1.1  mrg      <p>The default value refers to the FSF's GCC bug tracker.
    109  1.1  mrg 
    110  1.1  mrg    </dl>
    111  1.1  mrg 
    112  1.1  mrg <h3 class="heading"><a name="TOC1"></a>Target specification</h3>
    113  1.1  mrg 
    114  1.1  mrg      <ul>
    115  1.1  mrg <li>GCC has code to correctly determine the correct value for <var>target</var>
    116  1.1  mrg for nearly all native systems.  Therefore, we highly recommend you do
    117  1.1  mrg not provide a configure target when configuring a native compiler.
    118  1.1  mrg 
    119  1.1  mrg      <li><var>target</var> must be specified as <samp><span class="option">--target=</span><var>target</var></samp>
    120  1.1  mrg when configuring a cross compiler; examples of valid targets would be
    121  1.1  mrg m68k-elf, sh-elf, etc.
    122  1.1  mrg 
    123  1.1  mrg      <li>Specifying just <var>target</var> instead of <samp><span class="option">--target=</span><var>target</var></samp>
    124  1.1  mrg implies that the host defaults to <var>target</var>. 
    125  1.1  mrg </ul>
    126  1.1  mrg 
    127  1.1  mrg <h3 class="heading"><a name="TOC2"></a>Options specification</h3>
    128  1.1  mrg 
    129  1.1  mrg <p>Use <var>options</var> to override several configure time options for
    130  1.1  mrg GCC.  A list of supported <var>options</var> follows; &lsquo;<samp><span class="samp">configure
    131  1.1  mrg --help</span></samp>&rsquo; may list other options, but those not listed below may not
    132  1.1  mrg work and should not normally be used.
    133  1.1  mrg 
    134  1.1  mrg    <p>Note that each <samp><span class="option">--enable</span></samp> option has a corresponding
    135  1.1  mrg <samp><span class="option">--disable</span></samp> option and that each <samp><span class="option">--with</span></samp> option has a
    136  1.1  mrg corresponding <samp><span class="option">--without</span></samp> option.
    137  1.1  mrg 
    138  1.1  mrg      <dl>
    139  1.1  mrg <dt><code>--prefix=</code><var>dirname</var><dd>Specify the toplevel installation
    140  1.1  mrg directory.  This is the recommended way to install the tools into a directory
    141  1.1  mrg other than the default.  The toplevel installation directory defaults to
    142  1.1  mrg <samp><span class="file">/usr/local</span></samp>.
    143  1.1  mrg 
    144  1.1  mrg      <p>We <strong>highly</strong> recommend against <var>dirname</var> being the same or a
    145  1.1  mrg subdirectory of <var>objdir</var> or vice versa.  If specifying a directory
    146  1.1  mrg beneath a user's home directory tree, some shells will not expand
    147  1.1  mrg <var>dirname</var> correctly if it contains the &lsquo;<samp><span class="samp">~</span></samp>&rsquo; metacharacter; use
    148  1.1  mrg <samp><span class="env">$HOME</span></samp> instead.
    149  1.1  mrg 
    150  1.1  mrg      <p>The following standard <samp><span class="command">autoconf</span></samp> options are supported.  Normally you
    151  1.1  mrg should not need to use these options.
    152  1.1  mrg           <dl>
    153  1.1  mrg <dt><code>--exec-prefix=</code><var>dirname</var><dd>Specify the toplevel installation directory for architecture-dependent
    154  1.1  mrg files.  The default is <samp><var>prefix</var></samp>.
    155  1.1  mrg 
    156  1.1  mrg           <br><dt><code>--bindir=</code><var>dirname</var><dd>Specify the installation directory for the executables called by users
    157  1.1  mrg (such as <samp><span class="command">gcc</span></samp> and <samp><span class="command">g++</span></samp>).  The default is
    158  1.1  mrg <samp><var>exec-prefix</var><span class="file">/bin</span></samp>.
    159  1.1  mrg 
    160  1.1  mrg           <br><dt><code>--libdir=</code><var>dirname</var><dd>Specify the installation directory for object code libraries and
    161  1.1  mrg internal data files of GCC.  The default is <samp><var>exec-prefix</var><span class="file">/lib</span></samp>.
    162  1.1  mrg 
    163  1.1  mrg           <br><dt><code>--libexecdir=</code><var>dirname</var><dd>Specify the installation directory for internal executables of GCC. 
    164  1.1  mrg The default is <samp><var>exec-prefix</var><span class="file">/libexec</span></samp>.
    165  1.1  mrg 
    166  1.1  mrg           <br><dt><code>--with-slibdir=</code><var>dirname</var><dd>Specify the installation directory for the shared libgcc library.  The
    167  1.1  mrg default is <samp><var>libdir</var></samp>.
    168  1.1  mrg 
    169  1.1  mrg           <br><dt><code>--datarootdir=</code><var>dirname</var><dd>Specify the root of the directory tree for read-only architecture-independent
    170  1.1  mrg data files referenced by GCC.  The default is <samp><var>prefix</var><span class="file">/share</span></samp>.
    171  1.1  mrg 
    172  1.1  mrg           <br><dt><code>--infodir=</code><var>dirname</var><dd>Specify the installation directory for documentation in info format. 
    173  1.1  mrg The default is <samp><var>datarootdir</var><span class="file">/info</span></samp>.
    174  1.1  mrg 
    175  1.1  mrg           <br><dt><code>--datadir=</code><var>dirname</var><dd>Specify the installation directory for some architecture-independent
    176  1.1  mrg data files referenced by GCC.  The default is <samp><var>datarootdir</var></samp>.
    177  1.1  mrg 
    178  1.1  mrg           <br><dt><code>--docdir=</code><var>dirname</var><dd>Specify the installation directory for documentation files (other
    179  1.1  mrg than Info) for GCC.  The default is <samp><var>datarootdir</var><span class="file">/doc</span></samp>.
    180  1.1  mrg 
    181  1.1  mrg           <br><dt><code>--htmldir=</code><var>dirname</var><dd>Specify the installation directory for HTML documentation files. 
    182  1.1  mrg The default is <samp><var>docdir</var></samp>.
    183  1.1  mrg 
    184  1.1  mrg           <br><dt><code>--pdfdir=</code><var>dirname</var><dd>Specify the installation directory for PDF documentation files. 
    185  1.1  mrg The default is <samp><var>docdir</var></samp>.
    186  1.1  mrg 
    187  1.1  mrg           <br><dt><code>--mandir=</code><var>dirname</var><dd>Specify the installation directory for manual pages.  The default is
    188  1.1  mrg <samp><var>datarootdir</var><span class="file">/man</span></samp>.  (Note that the manual pages are only extracts
    189  1.1  mrg from the full GCC manuals, which are provided in Texinfo format.  The manpages
    190  1.1  mrg are derived by an automatic conversion process from parts of the full
    191  1.1  mrg manual.)
    192  1.1  mrg 
    193  1.1  mrg           <br><dt><code>--with-gxx-include-dir=</code><var>dirname</var><dd>Specify
    194  1.1  mrg the installation directory for G++ header files.  The default depends
    195  1.1  mrg on other configuration options, and differs between cross and native
    196  1.1  mrg configurations.
    197  1.1  mrg 
    198  1.3  mrg           <br><dt><code>--with-specs=</code><var>specs</var><dd>Specify additional command line driver SPECS. 
    199  1.3  mrg This can be useful if you need to turn on a non-standard feature by
    200  1.3  mrg default without modifying the compiler's source code, for instance
    201  1.3  mrg <samp><span class="option">--with-specs=%{!fcommon:%{!fno-common:-fno-common}}</span></samp>. 
    202  1.3  mrg See &ldquo;Spec Files&rdquo; in the main manual
    203  1.3  mrg 
    204  1.1  mrg      </dl>
    205  1.1  mrg 
    206  1.1  mrg      <br><dt><code>--program-prefix=</code><var>prefix</var><dd>GCC supports some transformations of the names of its programs when
    207  1.1  mrg installing them.  This option prepends <var>prefix</var> to the names of
    208  1.1  mrg programs to install in <var>bindir</var> (see above).  For example, specifying
    209  1.1  mrg <samp><span class="option">--program-prefix=foo-</span></samp> would result in &lsquo;<samp><span class="samp">gcc</span></samp>&rsquo;
    210  1.1  mrg being installed as <samp><span class="file">/usr/local/bin/foo-gcc</span></samp>.
    211  1.1  mrg 
    212  1.1  mrg      <br><dt><code>--program-suffix=</code><var>suffix</var><dd>Appends <var>suffix</var> to the names of programs to install in <var>bindir</var>
    213  1.1  mrg (see above).  For example, specifying <samp><span class="option">--program-suffix=-3.1</span></samp>
    214  1.1  mrg would result in &lsquo;<samp><span class="samp">gcc</span></samp>&rsquo; being installed as
    215  1.1  mrg <samp><span class="file">/usr/local/bin/gcc-3.1</span></samp>.
    216  1.1  mrg 
    217  1.1  mrg      <br><dt><code>--program-transform-name=</code><var>pattern</var><dd>Applies the &lsquo;<samp><span class="samp">sed</span></samp>&rsquo; script <var>pattern</var> to be applied to the names
    218  1.1  mrg of programs to install in <var>bindir</var> (see above).  <var>pattern</var> has to
    219  1.1  mrg consist of one or more basic &lsquo;<samp><span class="samp">sed</span></samp>&rsquo; editing commands, separated by
    220  1.1  mrg semicolons.  For example, if you want the &lsquo;<samp><span class="samp">gcc</span></samp>&rsquo; program name to be
    221  1.1  mrg transformed to the installed program <samp><span class="file">/usr/local/bin/myowngcc</span></samp> and
    222  1.1  mrg the &lsquo;<samp><span class="samp">g++</span></samp>&rsquo; program name to be transformed to
    223  1.1  mrg <samp><span class="file">/usr/local/bin/gspecial++</span></samp> without changing other program names,
    224  1.1  mrg you could use the pattern
    225  1.1  mrg <samp><span class="option">--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'</span></samp>
    226  1.1  mrg to achieve this effect.
    227  1.1  mrg 
    228  1.1  mrg      <p>All three options can be combined and used together, resulting in more
    229  1.1  mrg complex conversion patterns.  As a basic rule, <var>prefix</var> (and
    230  1.1  mrg <var>suffix</var>) are prepended (appended) before further transformations
    231  1.1  mrg can happen with a special transformation script <var>pattern</var>.
    232  1.1  mrg 
    233  1.1  mrg      <p>As currently implemented, this option only takes effect for native
    234  1.1  mrg builds; cross compiler binaries' names are not transformed even when a
    235  1.1  mrg transformation is explicitly asked for by one of these options.
    236  1.1  mrg 
    237  1.1  mrg      <p>For native builds, some of the installed programs are also installed
    238  1.1  mrg with the target alias in front of their name, as in
    239  1.1  mrg &lsquo;<samp><span class="samp">i686-pc-linux-gnu-gcc</span></samp>&rsquo;.  All of the above transformations happen
    240  1.1  mrg before the target alias is prepended to the name&mdash;so, specifying
    241  1.1  mrg <samp><span class="option">--program-prefix=foo-</span></samp> and <samp><span class="option">program-suffix=-3.1</span></samp>, the
    242  1.1  mrg resulting binary would be installed as
    243  1.1  mrg <samp><span class="file">/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1</span></samp>.
    244  1.1  mrg 
    245  1.1  mrg      <p>As a last shortcoming, none of the installed Ada programs are
    246  1.1  mrg transformed yet, which will be fixed in some time.
    247  1.1  mrg 
    248  1.1  mrg      <br><dt><code>--with-local-prefix=</code><var>dirname</var><dd>Specify the
    249  1.1  mrg installation directory for local include files.  The default is
    250  1.1  mrg <samp><span class="file">/usr/local</span></samp>.  Specify this option if you want the compiler to
    251  1.1  mrg search directory <samp><var>dirname</var><span class="file">/include</span></samp> for locally installed
    252  1.1  mrg header files <em>instead</em> of <samp><span class="file">/usr/local/include</span></samp>.
    253  1.1  mrg 
    254  1.1  mrg      <p>You should specify <samp><span class="option">--with-local-prefix</span></samp> <strong>only</strong> if your
    255  1.1  mrg site has a different convention (not <samp><span class="file">/usr/local</span></samp>) for where to put
    256  1.1  mrg site-specific files.
    257  1.1  mrg 
    258  1.1  mrg      <p>The default value for <samp><span class="option">--with-local-prefix</span></samp> is <samp><span class="file">/usr/local</span></samp>
    259  1.1  mrg regardless of the value of <samp><span class="option">--prefix</span></samp>.  Specifying
    260  1.1  mrg <samp><span class="option">--prefix</span></samp> has no effect on which directory GCC searches for
    261  1.1  mrg local header files.  This may seem counterintuitive, but actually it is
    262  1.1  mrg logical.
    263  1.1  mrg 
    264  1.1  mrg      <p>The purpose of <samp><span class="option">--prefix</span></samp> is to specify where to <em>install
    265  1.1  mrg GCC</em>.  The local header files in <samp><span class="file">/usr/local/include</span></samp>&mdash;if you put
    266  1.1  mrg any in that directory&mdash;are not part of GCC.  They are part of other
    267  1.1  mrg programs&mdash;perhaps many others.  (GCC installs its own header files in
    268  1.1  mrg another directory which is based on the <samp><span class="option">--prefix</span></samp> value.)
    269  1.1  mrg 
    270  1.1  mrg      <p>Both the local-prefix include directory and the GCC-prefix include
    271  1.1  mrg directory are part of GCC's &ldquo;system include&rdquo; directories.  Although these
    272  1.1  mrg two directories are not fixed, they need to be searched in the proper
    273  1.1  mrg order for the correct processing of the include_next directive.  The
    274  1.1  mrg local-prefix include directory is searched before the GCC-prefix
    275  1.1  mrg include directory.  Another characteristic of system include directories
    276  1.1  mrg is that pedantic warnings are turned off for headers in these directories.
    277  1.1  mrg 
    278  1.1  mrg      <p>Some autoconf macros add <samp><span class="option">-I </span><var>directory</var></samp> options to the
    279  1.1  mrg compiler command line, to ensure that directories containing installed
    280  1.1  mrg packages' headers are searched.  When <var>directory</var> is one of GCC's
    281  1.1  mrg system include directories, GCC will ignore the option so that system
    282  1.1  mrg directories continue to be processed in the correct order.  This
    283  1.1  mrg may result in a search order different from what was specified but the
    284  1.1  mrg directory will still be searched.
    285  1.1  mrg 
    286  1.1  mrg      <p>GCC automatically searches for ordinary libraries using
    287  1.1  mrg <samp><span class="env">GCC_EXEC_PREFIX</span></samp>.  Thus, when the same installation prefix is
    288  1.1  mrg used for both GCC and packages, GCC will automatically search for
    289  1.1  mrg both headers and libraries.  This provides a configuration that is
    290  1.1  mrg easy to use.  GCC behaves in a manner similar to that when it is
    291  1.1  mrg installed as a system compiler in <samp><span class="file">/usr</span></samp>.
    292  1.1  mrg 
    293  1.1  mrg      <p>Sites that need to install multiple versions of GCC may not want to
    294  1.1  mrg use the above simple configuration.  It is possible to use the
    295  1.1  mrg <samp><span class="option">--program-prefix</span></samp>, <samp><span class="option">--program-suffix</span></samp> and
    296  1.1  mrg <samp><span class="option">--program-transform-name</span></samp> options to install multiple versions
    297  1.1  mrg into a single directory, but it may be simpler to use different prefixes
    298  1.1  mrg and the <samp><span class="option">--with-local-prefix</span></samp> option to specify the location of the
    299  1.1  mrg site-specific files for each version.  It will then be necessary for
    300  1.1  mrg users to specify explicitly the location of local site libraries
    301  1.1  mrg (e.g., with <samp><span class="env">LIBRARY_PATH</span></samp>).
    302  1.1  mrg 
    303  1.1  mrg      <p>The same value can be used for both <samp><span class="option">--with-local-prefix</span></samp> and
    304  1.1  mrg <samp><span class="option">--prefix</span></samp> provided it is not <samp><span class="file">/usr</span></samp>.  This can be used
    305  1.1  mrg to avoid the default search of <samp><span class="file">/usr/local/include</span></samp>.
    306  1.1  mrg 
    307  1.1  mrg      <p><strong>Do not</strong> specify <samp><span class="file">/usr</span></samp> as the <samp><span class="option">--with-local-prefix</span></samp>! 
    308  1.1  mrg The directory you use for <samp><span class="option">--with-local-prefix</span></samp> <strong>must not</strong>
    309  1.1  mrg contain any of the system's standard header files.  If it did contain
    310  1.1  mrg them, certain programs would be miscompiled (including GNU Emacs, on
    311  1.1  mrg certain targets), because this would override and nullify the header
    312  1.1  mrg file corrections made by the <samp><span class="command">fixincludes</span></samp> script.
    313  1.1  mrg 
    314  1.1  mrg      <p>Indications are that people who use this option use it based on mistaken
    315  1.1  mrg ideas of what it is for.  People use it as if it specified where to
    316  1.1  mrg install part of GCC.  Perhaps they make this assumption because
    317  1.1  mrg installing GCC creates the directory.
    318  1.1  mrg 
    319  1.3  mrg      <br><dt><code>--with-native-system-header-dir=</code><var>dirname</var><dd>Specifies that <var>dirname</var> is the directory that contains native system
    320  1.3  mrg header files, rather than <samp><span class="file">/usr/include</span></samp>.  This option is most useful
    321  1.3  mrg if you are creating a compiler that should be isolated from the system
    322  1.3  mrg as much as possible.  It is most commonly used with the
    323  1.3  mrg <samp><span class="option">--with-sysroot</span></samp> option and will cause GCC to search
    324  1.3  mrg <var>dirname</var> inside the system root specified by that option.
    325  1.3  mrg 
    326  1.1  mrg      <br><dt><code>--enable-shared[=</code><var>package</var><code>[,...]]</code><dd>Build shared versions of libraries, if shared libraries are supported on
    327  1.1  mrg the target platform.  Unlike GCC 2.95.x and earlier, shared libraries
    328  1.1  mrg are enabled by default on all platforms that support shared libraries.
    329  1.1  mrg 
    330  1.1  mrg      <p>If a list of packages is given as an argument, build shared libraries
    331  1.1  mrg only for the listed packages.  For other packages, only static libraries
    332  1.1  mrg will be built.  Package names currently recognized in the GCC tree are
    333  1.1  mrg &lsquo;<samp><span class="samp">libgcc</span></samp>&rsquo; (also known as &lsquo;<samp><span class="samp">gcc</span></samp>&rsquo;), &lsquo;<samp><span class="samp">libstdc++</span></samp>&rsquo; (not
    334  1.1  mrg &lsquo;<samp><span class="samp">libstdc++-v3</span></samp>&rsquo;), &lsquo;<samp><span class="samp">libffi</span></samp>&rsquo;, &lsquo;<samp><span class="samp">zlib</span></samp>&rsquo;, &lsquo;<samp><span class="samp">boehm-gc</span></samp>&rsquo;,
    335  1.3  mrg &lsquo;<samp><span class="samp">ada</span></samp>&rsquo;, &lsquo;<samp><span class="samp">libada</span></samp>&rsquo;, &lsquo;<samp><span class="samp">libjava</span></samp>&rsquo;, &lsquo;<samp><span class="samp">libgo</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">libobjc</span></samp>&rsquo;. 
    336  1.1  mrg Note &lsquo;<samp><span class="samp">libiberty</span></samp>&rsquo; does not support shared libraries at all.
    337  1.1  mrg 
    338  1.1  mrg      <p>Use <samp><span class="option">--disable-shared</span></samp> to build only static libraries.  Note that
    339  1.1  mrg <samp><span class="option">--disable-shared</span></samp> does not accept a list of package names as
    340  1.1  mrg argument, only <samp><span class="option">--enable-shared</span></samp> does.
    341  1.1  mrg 
    342  1.5  mrg      <p>Contrast with <samp><span class="option">--enable-host-shared</span></samp>, which affects <em>host</em>
    343  1.5  mrg code.
    344  1.5  mrg 
    345  1.5  mrg      <br><dt><code>--enable-host-shared</code><dd>Specify that the <em>host</em> code should be built into position-independent
    346  1.5  mrg machine code (with -fPIC), allowing it to be used within shared libraries,
    347  1.5  mrg but yielding a slightly slower compiler.
    348  1.5  mrg 
    349  1.5  mrg      <p>This option is required when building the libgccjit.so library.
    350  1.5  mrg 
    351  1.5  mrg      <p>Contrast with <samp><span class="option">--enable-shared</span></samp>, which affects <em>target</em>
    352  1.5  mrg libraries.
    353  1.5  mrg 
    354  1.1  mrg      <br><dt><code><a name="with_002dgnu_002das"></a>--with-gnu-as</code><dd>Specify that the compiler should assume that the
    355  1.1  mrg assembler it finds is the GNU assembler.  However, this does not modify
    356  1.1  mrg the rules to find an assembler and will result in confusion if the
    357  1.1  mrg assembler found is not actually the GNU assembler.  (Confusion may also
    358  1.1  mrg result if the compiler finds the GNU assembler but has not been
    359  1.1  mrg configured with <samp><span class="option">--with-gnu-as</span></samp>.)  If you have more than one
    360  1.1  mrg assembler installed on your system, you may want to use this option in
    361  1.1  mrg connection with <samp><span class="option">--with-as=</span><var>pathname</var></samp> or
    362  1.1  mrg <samp><span class="option">--with-build-time-tools=</span><var>pathname</var></samp>.
    363  1.1  mrg 
    364  1.1  mrg      <p>The following systems are the only ones where it makes a difference
    365  1.1  mrg whether you use the GNU assembler.  On any other system,
    366  1.1  mrg <samp><span class="option">--with-gnu-as</span></samp> has no effect.
    367  1.1  mrg 
    368  1.1  mrg           <ul>
    369  1.1  mrg <li>&lsquo;<samp><span class="samp">hppa1.0-</span><var>any</var><span class="samp">-</span><var>any</var></samp>&rsquo;
    370  1.1  mrg <li>&lsquo;<samp><span class="samp">hppa1.1-</span><var>any</var><span class="samp">-</span><var>any</var></samp>&rsquo;
    371  1.1  mrg <li>&lsquo;<samp><span class="samp">sparc-sun-solaris2.</span><var>any</var></samp>&rsquo;
    372  1.1  mrg <li>&lsquo;<samp><span class="samp">sparc64-</span><var>any</var><span class="samp">-solaris2.</span><var>any</var></samp>&rsquo;
    373  1.1  mrg </ul>
    374  1.1  mrg 
    375  1.1  mrg      <br><dt><code><a name="with_002das"></a>--with-as=</code><var>pathname</var><dd>Specify that the compiler should use the assembler pointed to by
    376  1.1  mrg <var>pathname</var>, rather than the one found by the standard rules to find
    377  1.1  mrg an assembler, which are:
    378  1.1  mrg           <ul>
    379  1.1  mrg <li>Unless GCC is being built with a cross compiler, check the
    380  1.1  mrg <samp><var>libexec</var><span class="file">/gcc/</span><var>target</var><span class="file">/</span><var>version</var></samp> directory. 
    381  1.1  mrg <var>libexec</var> defaults to <samp><var>exec-prefix</var><span class="file">/libexec</span></samp>;
    382  1.1  mrg <var>exec-prefix</var> defaults to <var>prefix</var>, which
    383  1.1  mrg defaults to <samp><span class="file">/usr/local</span></samp> unless overridden by the
    384  1.1  mrg <samp><span class="option">--prefix=</span><var>pathname</var></samp> switch described above.  <var>target</var>
    385  1.1  mrg is the target system triple, such as &lsquo;<samp><span class="samp">sparc-sun-solaris2.7</span></samp>&rsquo;, and
    386  1.1  mrg <var>version</var> denotes the GCC version, such as 3.0.
    387  1.1  mrg 
    388  1.1  mrg           <li>If the target system is the same that you are building on, check
    389  1.1  mrg operating system specific directories (e.g. <samp><span class="file">/usr/ccs/bin</span></samp> on
    390  1.1  mrg Sun Solaris 2).
    391  1.1  mrg 
    392  1.1  mrg           <li>Check in the <samp><span class="env">PATH</span></samp> for a tool whose name is prefixed by the
    393  1.1  mrg target system triple.
    394  1.1  mrg 
    395  1.1  mrg           <li>Check in the <samp><span class="env">PATH</span></samp> for a tool whose name is not prefixed by the
    396  1.1  mrg target system triple, if the host and target system triple are
    397  1.1  mrg the same (in other words, we use a host tool if it can be used for
    398  1.1  mrg the target as well). 
    399  1.1  mrg </ul>
    400  1.1  mrg 
    401  1.1  mrg      <p>You may want to use <samp><span class="option">--with-as</span></samp> if no assembler
    402  1.1  mrg is installed in the directories listed above, or if you have multiple
    403  1.1  mrg assemblers installed and want to choose one that is not found by the
    404  1.1  mrg above rules.
    405  1.1  mrg 
    406  1.1  mrg      <br><dt><code><a name="with_002dgnu_002dld"></a>--with-gnu-ld</code><dd>Same as <a href="#with-gnu-as"><samp><span class="option">--with-gnu-as</span></samp></a>
    407  1.1  mrg but for the linker.
    408  1.1  mrg 
    409  1.1  mrg      <br><dt><code>--with-ld=</code><var>pathname</var><dd>Same as <a href="#with-as"><samp><span class="option">--with-as</span></samp></a>
    410  1.1  mrg but for the linker.
    411  1.1  mrg 
    412  1.1  mrg      <br><dt><code>--with-stabs</code><dd>Specify that stabs debugging
    413  1.1  mrg information should be used instead of whatever format the host normally
    414  1.1  mrg uses.  Normally GCC uses the same debug format as the host system.
    415  1.1  mrg 
    416  1.1  mrg      <p>On MIPS based systems and on Alphas, you must specify whether you want
    417  1.1  mrg GCC to create the normal ECOFF debugging format, or to use BSD-style
    418  1.1  mrg stabs passed through the ECOFF symbol table.  The normal ECOFF debug
    419  1.1  mrg format cannot fully handle languages other than C.  BSD stabs format can
    420  1.1  mrg handle other languages, but it only works with the GNU debugger GDB.
    421  1.1  mrg 
    422  1.1  mrg      <p>Normally, GCC uses the ECOFF debugging format by default; if you
    423  1.1  mrg prefer BSD stabs, specify <samp><span class="option">--with-stabs</span></samp> when you configure GCC.
    424  1.1  mrg 
    425  1.1  mrg      <p>No matter which default you choose when you configure GCC, the user
    426  1.1  mrg can use the <samp><span class="option">-gcoff</span></samp> and <samp><span class="option">-gstabs+</span></samp> options to specify explicitly
    427  1.1  mrg the debug format for a particular compilation.
    428  1.1  mrg 
    429  1.1  mrg      <p><samp><span class="option">--with-stabs</span></samp> is meaningful on the ISC system on the 386, also, if
    430  1.1  mrg <samp><span class="option">--with-gas</span></samp> is used.  It selects use of stabs debugging
    431  1.1  mrg information embedded in COFF output.  This kind of debugging information
    432  1.1  mrg supports C++ well; ordinary COFF debugging information does not.
    433  1.1  mrg 
    434  1.1  mrg      <p><samp><span class="option">--with-stabs</span></samp> is also meaningful on 386 systems running SVR4.  It
    435  1.1  mrg selects use of stabs debugging information embedded in ELF output.  The
    436  1.1  mrg C++ compiler currently (2.6.0) does not support the DWARF debugging
    437  1.1  mrg information normally used on 386 SVR4 platforms; stabs provide a
    438  1.1  mrg workable alternative.  This requires gas and gdb, as the normal SVR4
    439  1.1  mrg tools can not generate or interpret stabs.
    440  1.1  mrg 
    441  1.3  mrg      <br><dt><code>--with-tls=</code><var>dialect</var><dd>Specify the default TLS dialect, for systems were there is a choice. 
    442  1.3  mrg For ARM targets, possible values for <var>dialect</var> are <code>gnu</code> or
    443  1.3  mrg <code>gnu2</code>, which select between the original GNU dialect and the GNU TLS
    444  1.3  mrg descriptor-based dialect.
    445  1.3  mrg 
    446  1.3  mrg      <br><dt><code>--enable-multiarch</code><dd>Specify whether to enable or disable multiarch support.  The default is
    447  1.3  mrg to check for glibc start files in a multiarch location, and enable it
    448  1.3  mrg if the files are found.  The auto detection is enabled for native builds,
    449  1.3  mrg and for cross builds configured with <samp><span class="option">--with-sysroot</span></samp>, and without
    450  1.3  mrg <samp><span class="option">--with-native-system-header-dir</span></samp>. 
    451  1.3  mrg More documentation about multiarch can be found at
    452  1.3  mrg <a href="http://wiki.debian.org/Multiarch">http://wiki.debian.org/Multiarch</a>.
    453  1.3  mrg 
    454  1.5  mrg      <br><dt><code>--enable-vtable-verify</code><dd>Specify whether to enable or disable the vtable verification feature. 
    455  1.5  mrg Enabling this feature causes libstdc++ to be built with its virtual calls
    456  1.5  mrg in verifiable mode.  This means that, when linked with libvtv, every
    457  1.5  mrg virtual call in libstdc++ will verify the vtable pointer through which the
    458  1.5  mrg call will be made before actually making the call.  If not linked with libvtv,
    459  1.5  mrg the verifier will call stub functions (in libstdc++ itself) and do nothing. 
    460  1.5  mrg If vtable verification is disabled, then libstdc++ is not built with its
    461  1.5  mrg virtual calls in verifiable mode at all.  However the libvtv library will
    462  1.5  mrg still be built (see <samp><span class="option">--disable-libvtv</span></samp> to turn off building libvtv). 
    463  1.5  mrg <samp><span class="option">--disable-vtable-verify</span></samp> is the default.
    464  1.5  mrg 
    465  1.1  mrg      <br><dt><code>--disable-multilib</code><dd>Specify that multiple target
    466  1.1  mrg libraries to support different target variants, calling
    467  1.1  mrg conventions, etc. should not be built.  The default is to build a
    468  1.1  mrg predefined set of them.
    469  1.1  mrg 
    470  1.1  mrg      <p>Some targets provide finer-grained control over which multilibs are built
    471  1.1  mrg (e.g., <samp><span class="option">--disable-softfloat</span></samp>):
    472  1.1  mrg           <dl>
    473  1.3  mrg <dt><code>arm-*-*</code><dd>fpu, 26bit, underscore, interwork, biendian, nofmult.
    474  1.1  mrg 
    475  1.1  mrg           <br><dt><code>m68*-*-*</code><dd>softfloat, m68881, m68000, m68020.
    476  1.1  mrg 
    477  1.1  mrg           <br><dt><code>mips*-*-*</code><dd>single-float, biendian, softfloat.
    478  1.1  mrg 
    479  1.1  mrg           <br><dt><code>powerpc*-*-*, rs6000*-*-*</code><dd>aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian,
    480  1.1  mrg sysv, aix.
    481  1.1  mrg 
    482  1.1  mrg      </dl>
    483  1.1  mrg 
    484  1.1  mrg      <br><dt><code>--with-multilib-list=</code><var>list</var><dt><code>--without-multilib-list</code><dd>Specify what multilibs to build. 
    485  1.3  mrg Currently only implemented for sh*-*-* and x86-64-*-linux*.
    486  1.1  mrg 
    487  1.3  mrg           <dl>
    488  1.3  mrg <dt><code>sh*-*-*</code><dd><var>list</var> is a comma separated list of CPU names.  These must be of the
    489  1.1  mrg form <code>sh*</code> or <code>m*</code> (in which case they match the compiler option
    490  1.1  mrg for that processor).  The list should not contain any endian options -
    491  1.1  mrg these are handled by <samp><span class="option">--with-endian</span></samp>.
    492  1.1  mrg 
    493  1.3  mrg           <p>If <var>list</var> is empty, then there will be no multilibs for extra
    494  1.1  mrg processors.  The multilib for the secondary endian remains enabled.
    495  1.1  mrg 
    496  1.3  mrg           <p>As a special case, if an entry in the list starts with a <code>!</code>
    497  1.1  mrg (exclamation point), then it is added to the list of excluded multilibs. 
    498  1.1  mrg Entries of this sort should be compatible with &lsquo;<samp><span class="samp">MULTILIB_EXCLUDES</span></samp>&rsquo;
    499  1.1  mrg (once the leading <code>!</code> has been stripped).
    500  1.1  mrg 
    501  1.3  mrg           <p>If <samp><span class="option">--with-multilib-list</span></samp> is not given, then a default set of
    502  1.1  mrg multilibs is selected based on the value of <samp><span class="option">--target</span></samp>.  This is
    503  1.1  mrg usually the complete set of libraries, but some targets imply a more
    504  1.1  mrg specialized subset.
    505  1.1  mrg 
    506  1.3  mrg           <p>Example 1: to configure a compiler for SH4A only, but supporting both
    507  1.1  mrg endians, with little endian being the default:
    508  1.3  mrg           <pre class="smallexample">               --with-cpu=sh4a --with-endian=little,big --with-multilib-list=
    509  1.1  mrg </pre>
    510  1.3  mrg           <p>Example 2: to configure a compiler for both SH4A and SH4AL-DSP, but with
    511  1.1  mrg only little endian SH4AL:
    512  1.3  mrg           <pre class="smallexample">               --with-cpu=sh4a --with-endian=little,big \
    513  1.3  mrg                --with-multilib-list=sh4al,!mb/m4al
    514  1.1  mrg </pre>
    515  1.3  mrg           <br><dt><code>x86-64-*-linux*</code><dd><var>list</var> is a comma separated list of <code>m32</code>, <code>m64</code> and
    516  1.3  mrg <code>mx32</code> to enable 32-bit, 64-bit and x32 run-time libraries,
    517  1.3  mrg respectively.  If <var>list</var> is empty, then there will be no multilibs
    518  1.3  mrg and only the default run-time library will be enabled.
    519  1.3  mrg 
    520  1.3  mrg           <p>If <samp><span class="option">--with-multilib-list</span></samp> is not given, then only 32-bit and
    521  1.3  mrg 64-bit run-time libraries will be enabled. 
    522  1.3  mrg </dl>
    523  1.3  mrg 
    524  1.1  mrg      <br><dt><code>--with-endian=</code><var>endians</var><dd>Specify what endians to use. 
    525  1.1  mrg Currently only implemented for sh*-*-*.
    526  1.1  mrg 
    527  1.1  mrg      <p><var>endians</var> may be one of the following:
    528  1.1  mrg           <dl>
    529  1.1  mrg <dt><code>big</code><dd>Use big endian exclusively. 
    530  1.1  mrg <br><dt><code>little</code><dd>Use little endian exclusively. 
    531  1.1  mrg <br><dt><code>big,little</code><dd>Use big endian by default.  Provide a multilib for little endian. 
    532  1.1  mrg <br><dt><code>little,big</code><dd>Use little endian by default.  Provide a multilib for big endian. 
    533  1.1  mrg </dl>
    534  1.1  mrg 
    535  1.1  mrg      <br><dt><code>--enable-threads</code><dd>Specify that the target
    536  1.1  mrg supports threads.  This affects the Objective-C compiler and runtime
    537  1.1  mrg library, and exception handling for other languages like C++ and Java. 
    538  1.1  mrg On some systems, this is the default.
    539  1.1  mrg 
    540  1.1  mrg      <p>In general, the best (and, in many cases, the only known) threading
    541  1.1  mrg model available will be configured for use.  Beware that on some
    542  1.1  mrg systems, GCC has not been taught what threading models are generally
    543  1.1  mrg available for the system.  In this case, <samp><span class="option">--enable-threads</span></samp> is an
    544  1.1  mrg alias for <samp><span class="option">--enable-threads=single</span></samp>.
    545  1.1  mrg 
    546  1.1  mrg      <br><dt><code>--disable-threads</code><dd>Specify that threading support should be disabled for the system. 
    547  1.1  mrg This is an alias for <samp><span class="option">--enable-threads=single</span></samp>.
    548  1.1  mrg 
    549  1.1  mrg      <br><dt><code>--enable-threads=</code><var>lib</var><dd>Specify that
    550  1.1  mrg <var>lib</var> is the thread support library.  This affects the Objective-C
    551  1.1  mrg compiler and runtime library, and exception handling for other languages
    552  1.1  mrg like C++ and Java.  The possibilities for <var>lib</var> are:
    553  1.1  mrg 
    554  1.1  mrg           <dl>
    555  1.1  mrg <dt><code>aix</code><dd>AIX thread support. 
    556  1.1  mrg <br><dt><code>dce</code><dd>DCE thread support. 
    557  1.3  mrg <br><dt><code>lynx</code><dd>LynxOS thread support. 
    558  1.3  mrg <br><dt><code>mipssde</code><dd>MIPS SDE thread support. 
    559  1.1  mrg <br><dt><code>no</code><dd>This is an alias for &lsquo;<samp><span class="samp">single</span></samp>&rsquo;. 
    560  1.1  mrg <br><dt><code>posix</code><dd>Generic POSIX/Unix98 thread support. 
    561  1.1  mrg <br><dt><code>rtems</code><dd>RTEMS thread support. 
    562  1.1  mrg <br><dt><code>single</code><dd>Disable thread support, should work for all platforms. 
    563  1.3  mrg <br><dt><code>tpf</code><dd>TPF thread support. 
    564  1.1  mrg <br><dt><code>vxworks</code><dd>VxWorks thread support. 
    565  1.1  mrg <br><dt><code>win32</code><dd>Microsoft Win32 API thread support. 
    566  1.1  mrg </dl>
    567  1.1  mrg 
    568  1.1  mrg      <br><dt><code>--enable-tls</code><dd>Specify that the target supports TLS (Thread Local Storage).  Usually
    569  1.1  mrg configure can correctly determine if TLS is supported.  In cases where
    570  1.1  mrg it guesses incorrectly, TLS can be explicitly enabled or disabled with
    571  1.1  mrg <samp><span class="option">--enable-tls</span></samp> or <samp><span class="option">--disable-tls</span></samp>.  This can happen if
    572  1.1  mrg the assembler supports TLS but the C library does not, or if the
    573  1.1  mrg assumptions made by the configure test are incorrect.
    574  1.1  mrg 
    575  1.1  mrg      <br><dt><code>--disable-tls</code><dd>Specify that the target does not support TLS. 
    576  1.1  mrg This is an alias for <samp><span class="option">--enable-tls=no</span></samp>.
    577  1.1  mrg 
    578  1.1  mrg      <br><dt><code>--with-cpu=</code><var>cpu</var><dt><code>--with-cpu-32=</code><var>cpu</var><dt><code>--with-cpu-64=</code><var>cpu</var><dd>Specify which cpu variant the compiler should generate code for by default. 
    579  1.1  mrg <var>cpu</var> will be used as the default value of the <samp><span class="option">-mcpu=</span></samp> switch. 
    580  1.5  mrg This option is only supported on some targets, including ARC, ARM, i386, M68k,
    581  1.5  mrg PowerPC, and SPARC.  It is mandatory for ARC.  The <samp><span class="option">--with-cpu-32</span></samp> and
    582  1.1  mrg <samp><span class="option">--with-cpu-64</span></samp> options specify separate default CPUs for
    583  1.1  mrg 32-bit and 64-bit modes; these options are only supported for i386,
    584  1.1  mrg x86-64 and PowerPC.
    585  1.1  mrg 
    586  1.1  mrg      <br><dt><code>--with-schedule=</code><var>cpu</var><dt><code>--with-arch=</code><var>cpu</var><dt><code>--with-arch-32=</code><var>cpu</var><dt><code>--with-arch-64=</code><var>cpu</var><dt><code>--with-tune=</code><var>cpu</var><dt><code>--with-tune-32=</code><var>cpu</var><dt><code>--with-tune-64=</code><var>cpu</var><dt><code>--with-abi=</code><var>abi</var><dt><code>--with-fpu=</code><var>type</var><dt><code>--with-float=</code><var>type</var><dd>These configure options provide default values for the <samp><span class="option">-mschedule=</span></samp>,
    587  1.1  mrg <samp><span class="option">-march=</span></samp>, <samp><span class="option">-mtune=</span></samp>, <samp><span class="option">-mabi=</span></samp>, and <samp><span class="option">-mfpu=</span></samp>
    588  1.1  mrg options and for <samp><span class="option">-mhard-float</span></samp> or <samp><span class="option">-msoft-float</span></samp>.  As with
    589  1.1  mrg <samp><span class="option">--with-cpu</span></samp>, which switches will be accepted and acceptable values
    590  1.1  mrg of the arguments depend on the target.
    591  1.1  mrg 
    592  1.1  mrg      <br><dt><code>--with-mode=</code><var>mode</var><dd>Specify if the compiler should default to <samp><span class="option">-marm</span></samp> or <samp><span class="option">-mthumb</span></samp>. 
    593  1.1  mrg This option is only supported on ARM targets.
    594  1.1  mrg 
    595  1.3  mrg      <br><dt><code>--with-stack-offset=</code><var>num</var><dd>This option sets the default for the -mstack-offset=<var>num</var> option,
    596  1.3  mrg and will thus generally also control the setting of this option for
    597  1.3  mrg libraries.  This option is only supported on Epiphany targets.
    598  1.3  mrg 
    599  1.3  mrg      <br><dt><code>--with-fpmath=</code><var>isa</var><dd>This options sets <samp><span class="option">-mfpmath=sse</span></samp> by default and specifies the default
    600  1.3  mrg ISA for floating-point arithmetics.  You can select either &lsquo;<samp><span class="samp">sse</span></samp>&rsquo; which
    601  1.3  mrg enables <samp><span class="option">-msse2</span></samp> or &lsquo;<samp><span class="samp">avx</span></samp>&rsquo; which enables <samp><span class="option">-mavx</span></samp> by default. 
    602  1.3  mrg This option is only supported on i386 and x86-64 targets.
    603  1.1  mrg 
    604  1.5  mrg      <br><dt><code>--with-fp-32=</code><var>mode</var><dd>On MIPS targets, set the default value for the <samp><span class="option">-mfp</span></samp> option when using
    605  1.5  mrg the o32 ABI.  The possibilities for <var>mode</var> are:
    606  1.5  mrg           <dl>
    607  1.5  mrg <dt><code>32</code><dd>Use the o32 FP32 ABI extension, as with the <samp><span class="option">-mfp32</span></samp> command-line
    608  1.5  mrg option. 
    609  1.5  mrg <br><dt><code>xx</code><dd>Use the o32 FPXX ABI extension, as with the <samp><span class="option">-mfpxx</span></samp> command-line
    610  1.5  mrg option. 
    611  1.5  mrg <br><dt><code>64</code><dd>Use the o32 FP64 ABI extension, as with the <samp><span class="option">-mfp64</span></samp> command-line
    612  1.5  mrg option. 
    613  1.5  mrg </dl>
    614  1.5  mrg      In the absence of this configuration option the default is to use the o32
    615  1.5  mrg FP32 ABI extension.
    616  1.5  mrg 
    617  1.5  mrg      <br><dt><code>--with-odd-spreg-32</code><dd>On MIPS targets, set the <samp><span class="option">-modd-spreg</span></samp> option by default when using
    618  1.5  mrg the o32 ABI.
    619  1.5  mrg 
    620  1.5  mrg      <br><dt><code>--without-odd-spreg-32</code><dd>On MIPS targets, set the <samp><span class="option">-mno-odd-spreg</span></samp> option by default when using
    621  1.5  mrg the o32 ABI.  This is normally used in conjunction with
    622  1.5  mrg <samp><span class="option">--with-fp-32=64</span></samp> in order to target the o32 FP64A ABI extension.
    623  1.5  mrg 
    624  1.5  mrg      <br><dt><code>--with-nan=</code><var>encoding</var><dd>On MIPS targets, set the default encoding convention to use for the
    625  1.5  mrg special not-a-number (NaN) IEEE 754 floating-point data.  The
    626  1.5  mrg possibilities for <var>encoding</var> are:
    627  1.5  mrg           <dl>
    628  1.5  mrg <dt><code>legacy</code><dd>Use the legacy encoding, as with the <samp><span class="option">-mnan=legacy</span></samp> command-line
    629  1.5  mrg option. 
    630  1.5  mrg <br><dt><code>2008</code><dd>Use the 754-2008 encoding, as with the <samp><span class="option">-mnan=2008</span></samp> command-line
    631  1.5  mrg option. 
    632  1.5  mrg </dl>
    633  1.5  mrg      To use this configuration option you must have an assembler version
    634  1.5  mrg installed that supports the <samp><span class="option">-mnan=</span></samp> command-line option too. 
    635  1.5  mrg In the absence of this configuration option the default convention is
    636  1.5  mrg the legacy encoding, as when neither of the <samp><span class="option">-mnan=2008</span></samp> and
    637  1.5  mrg <samp><span class="option">-mnan=legacy</span></samp> command-line options has been used.
    638  1.5  mrg 
    639  1.1  mrg      <br><dt><code>--with-divide=</code><var>type</var><dd>Specify how the compiler should generate code for checking for
    640  1.1  mrg division by zero.  This option is only supported on the MIPS target. 
    641  1.1  mrg The possibilities for <var>type</var> are:
    642  1.1  mrg           <dl>
    643  1.1  mrg <dt><code>traps</code><dd>Division by zero checks use conditional traps (this is the default on
    644  1.1  mrg systems that support conditional traps). 
    645  1.1  mrg <br><dt><code>breaks</code><dd>Division by zero checks use the break instruction. 
    646  1.1  mrg </dl>
    647  1.1  mrg 
    648  1.1  mrg      <!-- If you make -with-llsc the default for additional targets, -->
    649  1.1  mrg      <!-- update the -with-llsc description in the MIPS section below. -->
    650  1.1  mrg      <br><dt><code>--with-llsc</code><dd>On MIPS targets, make <samp><span class="option">-mllsc</span></samp> the default when no
    651  1.1  mrg <samp><span class="option">-mno-llsc</span></samp> option is passed.  This is the default for
    652  1.1  mrg Linux-based targets, as the kernel will emulate them if the ISA does
    653  1.1  mrg not provide them.
    654  1.1  mrg 
    655  1.1  mrg      <br><dt><code>--without-llsc</code><dd>On MIPS targets, make <samp><span class="option">-mno-llsc</span></samp> the default when no
    656  1.1  mrg <samp><span class="option">-mllsc</span></samp> option is passed.
    657  1.1  mrg 
    658  1.1  mrg      <br><dt><code>--with-synci</code><dd>On MIPS targets, make <samp><span class="option">-msynci</span></samp> the default when no
    659  1.1  mrg <samp><span class="option">-mno-synci</span></samp> option is passed.
    660  1.1  mrg 
    661  1.1  mrg      <br><dt><code>--without-synci</code><dd>On MIPS targets, make <samp><span class="option">-mno-synci</span></samp> the default when no
    662  1.1  mrg <samp><span class="option">-msynci</span></samp> option is passed.  This is the default.
    663  1.1  mrg 
    664  1.1  mrg      <br><dt><code>--with-mips-plt</code><dd>On MIPS targets, make use of copy relocations and PLTs. 
    665  1.1  mrg These features are extensions to the traditional
    666  1.1  mrg SVR4-based MIPS ABIs and require support from GNU binutils
    667  1.1  mrg and the runtime C library.
    668  1.1  mrg 
    669  1.1  mrg      <br><dt><code>--enable-__cxa_atexit</code><dd>Define if you want to use __cxa_atexit, rather than atexit, to
    670  1.1  mrg register C++ destructors for local statics and global objects. 
    671  1.1  mrg This is essential for fully standards-compliant handling of
    672  1.1  mrg destructors, but requires __cxa_atexit in libc.  This option is currently
    673  1.1  mrg only available on systems with GNU libc.  When enabled, this will cause
    674  1.1  mrg <samp><span class="option">-fuse-cxa-atexit</span></samp> to be passed by default.
    675  1.1  mrg 
    676  1.3  mrg      <br><dt><code>--enable-gnu-indirect-function</code><dd>Define if you want to enable the <code>ifunc</code> attribute.  This option is
    677  1.3  mrg currently only available on systems with GNU libc on certain targets.
    678  1.3  mrg 
    679  1.1  mrg      <br><dt><code>--enable-target-optspace</code><dd>Specify that target
    680  1.1  mrg libraries should be optimized for code space instead of code speed. 
    681  1.1  mrg This is the default for the m32r platform.
    682  1.1  mrg 
    683  1.1  mrg      <br><dt><code>--with-cpp-install-dir=</code><var>dirname</var><dd>Specify that the user visible <samp><span class="command">cpp</span></samp> program should be installed
    684  1.1  mrg in <samp><var>prefix</var><span class="file">/</span><var>dirname</var><span class="file">/cpp</span></samp>, in addition to <var>bindir</var>.
    685  1.1  mrg 
    686  1.1  mrg      <br><dt><code>--enable-comdat</code><dd>Enable COMDAT group support.  This is primarily used to override the
    687  1.1  mrg automatically detected value.
    688  1.1  mrg 
    689  1.1  mrg      <br><dt><code>--enable-initfini-array</code><dd>Force the use of sections <code>.init_array</code> and <code>.fini_array</code>
    690  1.1  mrg (instead of <code>.init</code> and <code>.fini</code>) for constructors and
    691  1.1  mrg destructors.  Option <samp><span class="option">--disable-initfini-array</span></samp> has the
    692  1.1  mrg opposite effect.  If neither option is specified, the configure script
    693  1.1  mrg will try to guess whether the <code>.init_array</code> and
    694  1.1  mrg <code>.fini_array</code> sections are supported and, if they are, use them.
    695  1.1  mrg 
    696  1.5  mrg      <br><dt><code>--enable-link-mutex</code><dd>When building GCC, use a mutex to avoid linking the compilers for
    697  1.5  mrg multiple languages at the same time, to avoid thrashing on build
    698  1.5  mrg systems with limited free memory.  The default is not to use such a mutex.
    699  1.5  mrg 
    700  1.1  mrg      <br><dt><code>--enable-maintainer-mode</code><dd>The build rules that regenerate the Autoconf and Automake output files as
    701  1.1  mrg well as the GCC master message catalog <samp><span class="file">gcc.pot</span></samp> are normally
    702  1.1  mrg disabled.  This is because it can only be rebuilt if the complete source
    703  1.1  mrg tree is present.  If you have changed the sources and want to rebuild the
    704  1.1  mrg catalog, configuring with <samp><span class="option">--enable-maintainer-mode</span></samp> will enable
    705  1.1  mrg this.  Note that you need a recent version of the <code>gettext</code> tools
    706  1.1  mrg to do so.
    707  1.1  mrg 
    708  1.1  mrg      <br><dt><code>--disable-bootstrap</code><dd>For a native build, the default configuration is to perform
    709  1.1  mrg a 3-stage bootstrap of the compiler when &lsquo;<samp><span class="samp">make</span></samp>&rsquo; is invoked,
    710  1.1  mrg testing that GCC can compile itself correctly.  If you want to disable
    711  1.1  mrg this process, you can configure with <samp><span class="option">--disable-bootstrap</span></samp>.
    712  1.1  mrg 
    713  1.1  mrg      <br><dt><code>--enable-bootstrap</code><dd>In special cases, you may want to perform a 3-stage build
    714  1.1  mrg even if the target and host triplets are different. 
    715  1.1  mrg This is possible when the host can run code compiled for
    716  1.1  mrg the target (e.g. host is i686-linux, target is i486-linux). 
    717  1.1  mrg Starting from GCC 4.2, to do this you have to configure explicitly
    718  1.1  mrg with <samp><span class="option">--enable-bootstrap</span></samp>.
    719  1.1  mrg 
    720  1.1  mrg      <br><dt><code>--enable-generated-files-in-srcdir</code><dd>Neither the .c and .h files that are generated from Bison and flex nor the
    721  1.1  mrg info manuals and man pages that are built from the .texi files are present
    722  1.1  mrg in the SVN development tree.  When building GCC from that development tree,
    723  1.1  mrg or from one of our snapshots, those generated files are placed in your
    724  1.1  mrg build directory, which allows for the source to be in a readonly
    725  1.1  mrg directory.
    726  1.1  mrg 
    727  1.1  mrg      <p>If you configure with <samp><span class="option">--enable-generated-files-in-srcdir</span></samp> then those
    728  1.1  mrg generated files will go into the source directory.  This is mainly intended
    729  1.1  mrg for generating release or prerelease tarballs of the GCC sources, since it
    730  1.1  mrg is not a requirement that the users of source releases to have flex, Bison,
    731  1.1  mrg or makeinfo.
    732  1.1  mrg 
    733  1.1  mrg      <br><dt><code>--enable-version-specific-runtime-libs</code><dd>Specify
    734  1.1  mrg that runtime libraries should be installed in the compiler specific
    735  1.1  mrg subdirectory (<samp><var>libdir</var><span class="file">/gcc</span></samp>) rather than the usual places.  In
    736  1.1  mrg addition, &lsquo;<samp><span class="samp">libstdc++</span></samp>&rsquo;'s include files will be installed into
    737  1.1  mrg <samp><var>libdir</var></samp> unless you overruled it by using
    738  1.1  mrg <samp><span class="option">--with-gxx-include-dir=</span><var>dirname</var></samp>.  Using this option is
    739  1.1  mrg particularly useful if you intend to use several versions of GCC in
    740  1.1  mrg parallel.  This is currently supported by &lsquo;<samp><span class="samp">libgfortran</span></samp>&rsquo;,
    741  1.5  mrg &lsquo;<samp><span class="samp">libjava</span></samp>&rsquo;, &lsquo;<samp><span class="samp">libstdc++</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">libobjc</span></samp>&rsquo;.
    742  1.5  mrg 
    743  1.5  mrg      <br><dt><code><a name="WithAixSoname"></a>--with-aix-soname=&lsquo;</code><samp><span class="samp">aix</span></samp><code>&rsquo;, &lsquo;</code><samp><span class="samp">svr4</span></samp><code>&rsquo; or &lsquo;</code><samp><span class="samp">both</span></samp><code>&rsquo;</code><dd>Traditional AIX shared library versioning (versioned <code>Shared Object</code>
    744  1.5  mrg files as members of unversioned <code>Archive Library</code> files named
    745  1.5  mrg &lsquo;<samp><span class="samp">lib.a</span></samp>&rsquo;) causes numerous headaches for package managers. However,
    746  1.5  mrg <code>Import Files</code> as members of <code>Archive Library</code> files allow for
    747  1.5  mrg <strong>filename-based versioning</strong> of shared libraries as seen on Linux/SVR4,
    748  1.5  mrg where this is called the "SONAME". But as they prevent static linking,
    749  1.5  mrg <code>Import Files</code> may be used with <code>Runtime Linking</code> only, where the
    750  1.5  mrg linker does search for &lsquo;<samp><span class="samp">libNAME.so</span></samp>&rsquo; before &lsquo;<samp><span class="samp">libNAME.a</span></samp>&rsquo; library
    751  1.5  mrg filenames with the &lsquo;<samp><span class="samp">-lNAME</span></samp>&rsquo; linker flag.
    752  1.5  mrg 
    753  1.5  mrg      <p><a name="AixLdCommand"></a>For detailed information please refer to the AIX
    754  1.5  mrg <a href="http://www-01.ibm.com/support/knowledgecenter/search/%22the%20ld%20command%2C%20also%20called%20the%20linkage%20editor%20or%20binder%22">ld Command</a> reference.
    755  1.5  mrg 
    756  1.5  mrg      <p>As long as shared library creation is enabled, upon:
    757  1.5  mrg           <dl>
    758  1.5  mrg <dt><code>--with-aix-soname=aix</code><br><dt><code>--with-aix-soname=both</code><dd> A (traditional AIX) <code>Shared Archive Library</code> file is created:
    759  1.5  mrg                <ul>
    760  1.5  mrg   <li>using the &lsquo;<samp><span class="samp">libNAME.a</span></samp>&rsquo; filename scheme
    761  1.5  mrg   <li>with the <code>Shared Object</code> file as archive member named
    762  1.5  mrg   &lsquo;<samp><span class="samp">libNAME.so.V</span></samp>&rsquo; (except for &lsquo;<samp><span class="samp">libgcc_s</span></samp>&rsquo;, where the <code>Shared
    763  1.5  mrg   Object</code> file is named &lsquo;<samp><span class="samp">shr.o</span></samp>&rsquo; for backwards compatibility), which
    764  1.5  mrg                     <ul>
    765  1.5  mrg    <li>is used for runtime loading from inside the &lsquo;<samp><span class="samp">libNAME.a</span></samp>&rsquo; file
    766  1.5  mrg    <li>is used for dynamic loading via
    767  1.5  mrg    <code>dlopen("libNAME.a(libNAME.so.V)", RTLD_MEMBER)</code>
    768  1.5  mrg    <li>is used for shared linking
    769  1.5  mrg    <li>is used for static linking, so no separate <code>Static Archive
    770  1.5  mrg    Library</code> file is needed
    771  1.5  mrg   </ul>
    772  1.5  mrg                 </ul>
    773  1.5  mrg           <br><dt><code>--with-aix-soname=both</code><br><dt><code>--with-aix-soname=svr4</code><dd> A (second) <code>Shared Archive Library</code> file is created:
    774  1.5  mrg                <ul>
    775  1.5  mrg  <li>using the &lsquo;<samp><span class="samp">libNAME.so.V</span></samp>&rsquo; filename scheme
    776  1.5  mrg  <li>with the <code>Shared Object</code> file as archive member named
    777  1.5  mrg  &lsquo;<samp><span class="samp">shr.o</span></samp>&rsquo;, which
    778  1.5  mrg                     <ul>
    779  1.5  mrg    <li>is created with the <code>-G linker flag</code>
    780  1.5  mrg    <li>has the <code>F_LOADONLY</code> flag set
    781  1.5  mrg    <li>is used for runtime loading from inside the &lsquo;<samp><span class="samp">libNAME.so.V</span></samp>&rsquo; file
    782  1.5  mrg    <li>is used for dynamic loading via <code>dlopen("libNAME.so.V(shr.o)",
    783  1.5  mrg    RTLD_MEMBER)</code>
    784  1.5  mrg   </ul>
    785  1.5  mrg                 <li>with the <code>Import File</code> as archive member named &lsquo;<samp><span class="samp">shr.imp</span></samp>&rsquo;,
    786  1.5  mrg  which
    787  1.5  mrg                     <ul>
    788  1.5  mrg    <li>refers to &lsquo;<samp><span class="samp">libNAME.so.V(shr.o)</span></samp>&rsquo; as the "SONAME", to be recorded
    789  1.5  mrg    in the <code>Loader Section</code> of subsequent binaries
    790  1.5  mrg    <li>indicates whether &lsquo;<samp><span class="samp">libNAME.so.V(shr.o)</span></samp>&rsquo; is 32 or 64 bit
    791  1.5  mrg    <li>lists all the public symbols exported by &lsquo;<samp><span class="samp">lib.so.V(shr.o)</span></samp>&rsquo;,
    792  1.5  mrg    eventually decorated with the <code>&lsquo;</code><samp><span class="samp">weak</span></samp><code>&rsquo; Keyword</code>
    793  1.5  mrg    <li>is necessary for shared linking against &lsquo;<samp><span class="samp">lib.so.V(shr.o)</span></samp>&rsquo;
    794  1.5  mrg    </ul>
    795  1.5  mrg                  </ul>
    796  1.5  mrg             A symbolic link using the &lsquo;<samp><span class="samp">libNAME.so</span></samp>&rsquo; filename scheme is created:
    797  1.5  mrg                <ul>
    798  1.5  mrg   <li>pointing to the &lsquo;<samp><span class="samp">libNAME.so.V</span></samp>&rsquo; <code>Shared Archive Library</code> file
    799  1.5  mrg   <li>to permit the <code>ld Command</code> to find &lsquo;<samp><span class="samp">lib.so.V(shr.imp)</span></samp>&rsquo; via
    800  1.5  mrg   the &lsquo;<samp><span class="samp">-lNAME</span></samp>&rsquo; argument (requires <code>Runtime Linking</code> to be enabled)
    801  1.5  mrg   <li>to permit dynamic loading of &lsquo;<samp><span class="samp">lib.so.V(shr.o)</span></samp>&rsquo; without the need
    802  1.5  mrg   to specify the version number via <code>dlopen("libNAME.so(shr.o)",
    803  1.5  mrg   RTLD_MEMBER)</code>
    804  1.5  mrg   </ul>
    805  1.5  mrg           </dl>
    806  1.5  mrg 
    807  1.5  mrg      <p>As long as static library creation is enabled, upon:
    808  1.5  mrg           <dl>
    809  1.5  mrg <dt><code>--with-aix-soname=svr4</code><dd> A <code>Static Archive Library</code> is created:
    810  1.5  mrg                <ul>
    811  1.5  mrg  <li>using the &lsquo;<samp><span class="samp">libNAME.a</span></samp>&rsquo; filename scheme
    812  1.5  mrg  <li>with all the <code>Static Object</code> files as archive members, which
    813  1.5  mrg                     <ul>
    814  1.5  mrg    <li>are used for static linking
    815  1.5  mrg   </ul>
    816  1.5  mrg                 </ul>
    817  1.5  mrg           </dl>
    818  1.5  mrg 
    819  1.5  mrg      <p>While the aix-soname=&lsquo;<samp><span class="samp">svr4</span></samp>&rsquo; option does not create <code>Shared Object</code>
    820  1.5  mrg files as members of unversioned <code>Archive Library</code> files any more, package
    821  1.5  mrg managers still are responsible to
    822  1.5  mrg <a href="./specific.html#TransferAixShobj">transfer</a> <code>Shared Object</code> files
    823  1.5  mrg found as member of a previously installed unversioned <code>Archive Library</code>
    824  1.5  mrg file into the newly installed <code>Archive Library</code> file with the same
    825  1.5  mrg filename.
    826  1.5  mrg 
    827  1.5  mrg      <p><em>WARNING:</em> Creating <code>Shared Object</code> files with <code>Runtime Linking</code>
    828  1.5  mrg enabled may bloat the TOC, eventually leading to <code>TOC overflow</code> errors,
    829  1.5  mrg requiring the use of either the <samp><span class="option">-Wl,-bbigtoc</span></samp> linker flag (seen to
    830  1.5  mrg break with the <code>GDB</code> debugger) or some of the TOC-related compiler flags,
    831  1.5  mrg see &ldquo;RS/6000 and PowerPC Options&rdquo; in the main manual.
    832  1.5  mrg 
    833  1.5  mrg      <p><samp><span class="option">--with-aix-soname</span></samp> is currently supported by &lsquo;<samp><span class="samp">libgcc_s</span></samp>&rsquo; only, so
    834  1.5  mrg this option is still experimental and not for normal use yet.
    835  1.5  mrg 
    836  1.5  mrg      <p>Default is the traditional behaviour <samp><span class="option">--with-aix-soname=&lsquo;</span><samp><span class="samp">aix</span></samp><span class="option">&rsquo;</span></samp>.
    837  1.1  mrg 
    838  1.1  mrg      <br><dt><code>--enable-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that only a particular subset of compilers and
    839  1.1  mrg their runtime libraries should be built.  For a list of valid values for
    840  1.1  mrg <var>langN</var> you can issue the following command in the
    841  1.1  mrg <samp><span class="file">gcc</span></samp> directory of your GCC source tree:<br>
    842  1.1  mrg      <pre class="smallexample">          grep language= */config-lang.in
    843  1.1  mrg </pre>
    844  1.1  mrg      <p>Currently, you can use any of the following:
    845  1.3  mrg <code>all</code>, <code>ada</code>, <code>c</code>, <code>c++</code>, <code>fortran</code>,
    846  1.3  mrg <code>go</code>, <code>java</code>, <code>objc</code>, <code>obj-c++</code>. 
    847  1.1  mrg Building the Ada compiler has special requirements, see below. 
    848  1.1  mrg If you do not pass this flag, or specify the option <code>all</code>, then all
    849  1.1  mrg default languages available in the <samp><span class="file">gcc</span></samp> sub-tree will be configured. 
    850  1.3  mrg Ada, Go and Objective-C++ are not default languages; the rest are.
    851  1.1  mrg 
    852  1.1  mrg      <br><dt><code>--enable-stage1-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that a particular subset of compilers and their runtime
    853  1.1  mrg libraries should be built with the system C compiler during stage 1 of
    854  1.1  mrg the bootstrap process, rather than only in later stages with the
    855  1.1  mrg bootstrapped C compiler.  The list of valid values is the same as for
    856  1.1  mrg <samp><span class="option">--enable-languages</span></samp>, and the option <code>all</code> will select all
    857  1.1  mrg of the languages enabled by <samp><span class="option">--enable-languages</span></samp>.  This option is
    858  1.1  mrg primarily useful for GCC development; for instance, when a development
    859  1.1  mrg version of the compiler cannot bootstrap due to compiler bugs, or when
    860  1.1  mrg one is debugging front ends other than the C front end.  When this
    861  1.1  mrg option is used, one can then build the target libraries for the
    862  1.1  mrg specified languages with the stage-1 compiler by using <samp><span class="command">make
    863  1.1  mrg stage1-bubble all-target</span></samp>, or run the testsuite on the stage-1 compiler
    864  1.1  mrg for the specified languages using <samp><span class="command">make stage1-start check-gcc</span></samp>.
    865  1.1  mrg 
    866  1.1  mrg      <br><dt><code>--disable-libada</code><dd>Specify that the run-time libraries and tools used by GNAT should not
    867  1.1  mrg be built.  This can be useful for debugging, or for compatibility with
    868  1.1  mrg previous Ada build procedures, when it was required to explicitly
    869  1.1  mrg do a &lsquo;<samp><span class="samp">make -C gcc gnatlib_and_tools</span></samp>&rsquo;.
    870  1.1  mrg 
    871  1.5  mrg      <br><dt><code>--disable-libsanitizer</code><dd>Specify that the run-time libraries for the various sanitizers should
    872  1.5  mrg not be built.
    873  1.5  mrg 
    874  1.1  mrg      <br><dt><code>--disable-libssp</code><dd>Specify that the run-time libraries for stack smashing protection
    875  1.1  mrg should not be built.
    876  1.1  mrg 
    877  1.3  mrg      <br><dt><code>--disable-libquadmath</code><dd>Specify that the GCC quad-precision math library should not be built. 
    878  1.3  mrg On some systems, the library is required to be linkable when building
    879  1.3  mrg the Fortran front end, unless <samp><span class="option">--disable-libquadmath-support</span></samp>
    880  1.3  mrg is used.
    881  1.3  mrg 
    882  1.3  mrg      <br><dt><code>--disable-libquadmath-support</code><dd>Specify that the Fortran front end and <code>libgfortran</code> do not add
    883  1.3  mrg support for <code>libquadmath</code> on systems supporting it.
    884  1.3  mrg 
    885  1.5  mrg      <br><dt><code>--disable-libgomp</code><dd>Specify that the GNU Offloading and Multi Processing Runtime Library
    886  1.5  mrg should not be built.
    887  1.5  mrg 
    888  1.5  mrg      <br><dt><code>--disable-libvtv</code><dd>Specify that the run-time libraries used by vtable verification
    889  1.5  mrg should not be built.
    890  1.1  mrg 
    891  1.1  mrg      <br><dt><code>--with-dwarf2</code><dd>Specify that the compiler should
    892  1.1  mrg use DWARF 2 debugging information as the default.
    893  1.1  mrg 
    894  1.1  mrg      <br><dt><code>--enable-targets=all</code><dt><code>--enable-targets=</code><var>target_list</var><dd>Some GCC targets, e.g. powerpc64-linux, build bi-arch compilers. 
    895  1.1  mrg These are compilers that are able to generate either 64-bit or 32-bit
    896  1.1  mrg code.  Typically, the corresponding 32-bit target, e.g. 
    897  1.1  mrg powerpc-linux for powerpc64-linux, only generates 32-bit code.  This
    898  1.1  mrg option enables the 32-bit target to be a bi-arch compiler, which is
    899  1.1  mrg useful when you want a bi-arch compiler that defaults to 32-bit, and
    900  1.1  mrg you are building a bi-arch or multi-arch binutils in a combined tree. 
    901  1.1  mrg On mips-linux, this will build a tri-arch compiler (ABI o32/n32/64),
    902  1.1  mrg defaulted to o32. 
    903  1.3  mrg Currently, this option only affects sparc-linux, powerpc-linux, x86-linux,
    904  1.3  mrg mips-linux and s390-linux.
    905  1.1  mrg 
    906  1.1  mrg      <br><dt><code>--enable-secureplt</code><dd>This option enables <samp><span class="option">-msecure-plt</span></samp> by default for powerpc-linux. 
    907  1.1  mrg See &ldquo;RS/6000 and PowerPC Options&rdquo; in the main manual
    908  1.1  mrg 
    909  1.1  mrg      <br><dt><code>--enable-cld</code><dd>This option enables <samp><span class="option">-mcld</span></samp> by default for 32-bit x86 targets. 
    910  1.1  mrg See &ldquo;i386 and x86-64 Options&rdquo; in the main manual
    911  1.1  mrg 
    912  1.1  mrg      <br><dt><code>--enable-win32-registry</code><dt><code>--enable-win32-registry=</code><var>key</var><dt><code>--disable-win32-registry</code><dd>The <samp><span class="option">--enable-win32-registry</span></samp> option enables Microsoft Windows-hosted GCC
    913  1.1  mrg to look up installations paths in the registry using the following key:
    914  1.1  mrg 
    915  1.1  mrg      <pre class="smallexample">          <code>HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\</code><var>key</var>
    916  1.1  mrg </pre>
    917  1.1  mrg      <p><var>key</var> defaults to GCC version number, and can be overridden by the
    918  1.1  mrg <samp><span class="option">--enable-win32-registry=</span><var>key</var></samp> option.  Vendors and distributors
    919  1.1  mrg who use custom installers are encouraged to provide a different key,
    920  1.1  mrg perhaps one comprised of vendor name and GCC version number, to
    921  1.1  mrg avoid conflict with existing installations.  This feature is enabled
    922  1.1  mrg by default, and can be disabled by <samp><span class="option">--disable-win32-registry</span></samp>
    923  1.1  mrg option.  This option has no effect on the other hosts.
    924  1.1  mrg 
    925  1.1  mrg      <br><dt><code>--nfp</code><dd>Specify that the machine does not have a floating point unit.  This
    926  1.1  mrg option only applies to &lsquo;<samp><span class="samp">m68k-sun-sunos</span><var>n</var></samp>&rsquo;.  On any other
    927  1.1  mrg system, <samp><span class="option">--nfp</span></samp> has no effect.
    928  1.1  mrg 
    929  1.1  mrg      <br><dt><code>--enable-werror</code><dt><code>--disable-werror</code><dt><code>--enable-werror=yes</code><dt><code>--enable-werror=no</code><dd>When you specify this option, it controls whether certain files in the
    930  1.1  mrg compiler are built with <samp><span class="option">-Werror</span></samp> in bootstrap stage2 and later. 
    931  1.1  mrg If you don't specify it, <samp><span class="option">-Werror</span></samp> is turned on for the main
    932  1.1  mrg development trunk.  However it defaults to off for release branches and
    933  1.1  mrg final releases.  The specific files which get <samp><span class="option">-Werror</span></samp> are
    934  1.1  mrg controlled by the Makefiles.
    935  1.1  mrg 
    936  1.1  mrg      <br><dt><code>--enable-checking</code><dt><code>--enable-checking=</code><var>list</var><dd>When you specify this option, the compiler is built to perform internal
    937  1.1  mrg consistency checks of the requested complexity.  This does not change the
    938  1.1  mrg generated code, but adds error checking within the compiler.  This will
    939  1.1  mrg slow down the compiler and may only work properly if you are building
    940  1.1  mrg the compiler with GCC.  This is &lsquo;<samp><span class="samp">yes</span></samp>&rsquo; by default when building
    941  1.1  mrg from SVN or snapshots, but &lsquo;<samp><span class="samp">release</span></samp>&rsquo; for releases.  The default
    942  1.1  mrg for building the stage1 compiler is &lsquo;<samp><span class="samp">yes</span></samp>&rsquo;.  More control
    943  1.1  mrg over the checks may be had by specifying <var>list</var>.  The categories of
    944  1.1  mrg checks available are &lsquo;<samp><span class="samp">yes</span></samp>&rsquo; (most common checks
    945  1.1  mrg &lsquo;<samp><span class="samp">assert,misc,tree,gc,rtlflag,runtime</span></samp>&rsquo;), &lsquo;<samp><span class="samp">no</span></samp>&rsquo; (no checks at
    946  1.1  mrg all), &lsquo;<samp><span class="samp">all</span></samp>&rsquo; (all but &lsquo;<samp><span class="samp">valgrind</span></samp>&rsquo;), &lsquo;<samp><span class="samp">release</span></samp>&rsquo; (cheapest
    947  1.1  mrg checks &lsquo;<samp><span class="samp">assert,runtime</span></samp>&rsquo;) or &lsquo;<samp><span class="samp">none</span></samp>&rsquo; (same as &lsquo;<samp><span class="samp">no</span></samp>&rsquo;). 
    948  1.1  mrg Individual checks can be enabled with these flags &lsquo;<samp><span class="samp">assert</span></samp>&rsquo;,
    949  1.1  mrg &lsquo;<samp><span class="samp">df</span></samp>&rsquo;, &lsquo;<samp><span class="samp">fold</span></samp>&rsquo;, &lsquo;<samp><span class="samp">gc</span></samp>&rsquo;, &lsquo;<samp><span class="samp">gcac</span></samp>&rsquo; &lsquo;<samp><span class="samp">misc</span></samp>&rsquo;, &lsquo;<samp><span class="samp">rtl</span></samp>&rsquo;,
    950  1.1  mrg &lsquo;<samp><span class="samp">rtlflag</span></samp>&rsquo;, &lsquo;<samp><span class="samp">runtime</span></samp>&rsquo;, &lsquo;<samp><span class="samp">tree</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">valgrind</span></samp>&rsquo;.
    951  1.1  mrg 
    952  1.1  mrg      <p>The &lsquo;<samp><span class="samp">valgrind</span></samp>&rsquo; check requires the external <samp><span class="command">valgrind</span></samp>
    953  1.1  mrg simulator, available from <a href="http://valgrind.org/">http://valgrind.org/</a>.  The
    954  1.1  mrg &lsquo;<samp><span class="samp">df</span></samp>&rsquo;, &lsquo;<samp><span class="samp">rtl</span></samp>&rsquo;, &lsquo;<samp><span class="samp">gcac</span></samp>&rsquo; and &lsquo;<samp><span class="samp">valgrind</span></samp>&rsquo; checks are very expensive. 
    955  1.1  mrg To disable all checking, &lsquo;<samp><span class="samp">--disable-checking</span></samp>&rsquo; or
    956  1.1  mrg &lsquo;<samp><span class="samp">--enable-checking=none</span></samp>&rsquo; must be explicitly requested.  Disabling
    957  1.1  mrg assertions will make the compiler and runtime slightly faster but
    958  1.1  mrg increase the risk of undetected internal errors causing wrong code to be
    959  1.1  mrg generated.
    960  1.1  mrg 
    961  1.1  mrg      <br><dt><code>--disable-stage1-checking</code><dt><code>--enable-stage1-checking</code><dt><code>--enable-stage1-checking=</code><var>list</var><dd>If no <samp><span class="option">--enable-checking</span></samp> option is specified the stage1
    962  1.1  mrg compiler will be built with &lsquo;<samp><span class="samp">yes</span></samp>&rsquo; checking enabled, otherwise
    963  1.1  mrg the stage1 checking flags are the same as specified by
    964  1.1  mrg <samp><span class="option">--enable-checking</span></samp>.  To build the stage1 compiler with
    965  1.1  mrg different checking options use <samp><span class="option">--enable-stage1-checking</span></samp>. 
    966  1.1  mrg The list of checking options is the same as for <samp><span class="option">--enable-checking</span></samp>. 
    967  1.1  mrg If your system is too slow or too small to bootstrap a released compiler
    968  1.1  mrg with checking for stage1 enabled, you can use &lsquo;<samp><span class="samp">--disable-stage1-checking</span></samp>&rsquo;
    969  1.1  mrg to disable checking for the stage1 compiler.
    970  1.1  mrg 
    971  1.1  mrg      <br><dt><code>--enable-coverage</code><dt><code>--enable-coverage=</code><var>level</var><dd>With this option, the compiler is built to collect self coverage
    972  1.1  mrg information, every time it is run.  This is for internal development
    973  1.1  mrg purposes, and only works when the compiler is being built with gcc.  The
    974  1.1  mrg <var>level</var> argument controls whether the compiler is built optimized or
    975  1.1  mrg not, values are &lsquo;<samp><span class="samp">opt</span></samp>&rsquo; and &lsquo;<samp><span class="samp">noopt</span></samp>&rsquo;.  For coverage analysis you
    976  1.1  mrg want to disable optimization, for performance analysis you want to
    977  1.1  mrg enable optimization.  When coverage is enabled, the default level is
    978  1.1  mrg without optimization.
    979  1.1  mrg 
    980  1.1  mrg      <br><dt><code>--enable-gather-detailed-mem-stats</code><dd>When this option is specified more detailed information on memory
    981  1.1  mrg allocation is gathered.  This information is printed when using
    982  1.1  mrg <samp><span class="option">-fmem-report</span></samp>.
    983  1.1  mrg 
    984  1.1  mrg      <br><dt><code>--enable-nls</code><dt><code>--disable-nls</code><dd>The <samp><span class="option">--enable-nls</span></samp> option enables Native Language Support (NLS),
    985  1.1  mrg which lets GCC output diagnostics in languages other than American
    986  1.1  mrg English.  Native Language Support is enabled by default if not doing a
    987  1.1  mrg canadian cross build.  The <samp><span class="option">--disable-nls</span></samp> option disables NLS.
    988  1.1  mrg 
    989  1.1  mrg      <br><dt><code>--with-included-gettext</code><dd>If NLS is enabled, the <samp><span class="option">--with-included-gettext</span></samp> option causes the build
    990  1.1  mrg procedure to prefer its copy of GNU <samp><span class="command">gettext</span></samp>.
    991  1.1  mrg 
    992  1.1  mrg      <br><dt><code>--with-catgets</code><dd>If NLS is enabled, and if the host lacks <code>gettext</code> but has the
    993  1.1  mrg inferior <code>catgets</code> interface, the GCC build procedure normally
    994  1.1  mrg ignores <code>catgets</code> and instead uses GCC's copy of the GNU
    995  1.1  mrg <code>gettext</code> library.  The <samp><span class="option">--with-catgets</span></samp> option causes the
    996  1.1  mrg build procedure to use the host's <code>catgets</code> in this situation.
    997  1.1  mrg 
    998  1.1  mrg      <br><dt><code>--with-libiconv-prefix=</code><var>dir</var><dd>Search for libiconv header files in <samp><var>dir</var><span class="file">/include</span></samp> and
    999  1.1  mrg libiconv library files in <samp><var>dir</var><span class="file">/lib</span></samp>.
   1000  1.1  mrg 
   1001  1.1  mrg      <br><dt><code>--enable-obsolete</code><dd>Enable configuration for an obsoleted system.  If you attempt to
   1002  1.1  mrg configure GCC for a system (build, host, or target) which has been
   1003  1.1  mrg obsoleted, and you do not specify this flag, configure will halt with an
   1004  1.1  mrg error message.
   1005  1.1  mrg 
   1006  1.1  mrg      <p>All support for systems which have been obsoleted in one release of GCC
   1007  1.1  mrg is removed entirely in the next major release, unless someone steps
   1008  1.1  mrg forward to maintain the port.
   1009  1.1  mrg 
   1010  1.1  mrg      <br><dt><code>--enable-decimal-float</code><dt><code>--enable-decimal-float=yes</code><dt><code>--enable-decimal-float=no</code><dt><code>--enable-decimal-float=bid</code><dt><code>--enable-decimal-float=dpd</code><dt><code>--disable-decimal-float</code><dd>Enable (or disable) support for the C decimal floating point extension
   1011  1.1  mrg that is in the IEEE 754-2008 standard.  This is enabled by default only
   1012  1.1  mrg on PowerPC, i386, and x86_64 GNU/Linux systems.  Other systems may also
   1013  1.1  mrg support it, but require the user to specifically enable it.  You can
   1014  1.1  mrg optionally control which decimal floating point format is used (either
   1015  1.1  mrg &lsquo;<samp><span class="samp">bid</span></samp>&rsquo; or &lsquo;<samp><span class="samp">dpd</span></samp>&rsquo;).  The &lsquo;<samp><span class="samp">bid</span></samp>&rsquo; (binary integer decimal)
   1016  1.1  mrg format is default on i386 and x86_64 systems, and the &lsquo;<samp><span class="samp">dpd</span></samp>&rsquo;
   1017  1.1  mrg (densely packed decimal) format is default on PowerPC systems.
   1018  1.1  mrg 
   1019  1.1  mrg      <br><dt><code>--enable-fixed-point</code><dt><code>--disable-fixed-point</code><dd>Enable (or disable) support for C fixed-point arithmetic. 
   1020  1.1  mrg This option is enabled by default for some targets (such as MIPS) which
   1021  1.1  mrg have hardware-support for fixed-point operations.  On other targets, you
   1022  1.1  mrg may enable this option manually.
   1023  1.1  mrg 
   1024  1.1  mrg      <br><dt><code>--with-long-double-128</code><dd>Specify if <code>long double</code> type should be 128-bit by default on selected
   1025  1.1  mrg GNU/Linux architectures.  If using <code>--without-long-double-128</code>,
   1026  1.1  mrg <code>long double</code> will be by default 64-bit, the same as <code>double</code> type. 
   1027  1.1  mrg When neither of these configure options are used, the default will be
   1028  1.1  mrg 128-bit <code>long double</code> when built against GNU C Library 2.4 and later,
   1029  1.1  mrg 64-bit <code>long double</code> otherwise.
   1030  1.1  mrg 
   1031  1.3  mrg      <br><dt><code>--with-gmp=</code><var>pathname</var><dt><code>--with-gmp-include=</code><var>pathname</var><dt><code>--with-gmp-lib=</code><var>pathname</var><dt><code>--with-mpfr=</code><var>pathname</var><dt><code>--with-mpfr-include=</code><var>pathname</var><dt><code>--with-mpfr-lib=</code><var>pathname</var><dt><code>--with-mpc=</code><var>pathname</var><dt><code>--with-mpc-include=</code><var>pathname</var><dt><code>--with-mpc-lib=</code><var>pathname</var><dd>If you want to build GCC but do not have the GMP library, the MPFR
   1032  1.1  mrg library and/or the MPC library installed in a standard location and
   1033  1.3  mrg do not have their sources present in the GCC source tree then you
   1034  1.3  mrg can explicitly specify the directory where they are installed
   1035  1.3  mrg (&lsquo;<samp><span class="samp">--with-gmp=</span><var>gmpinstalldir</var></samp>&rsquo;,
   1036  1.1  mrg &lsquo;<samp><span class="samp">--with-mpfr=</span><var>mpfrinstalldir</var></samp>&rsquo;,
   1037  1.1  mrg &lsquo;<samp><span class="samp">--with-mpc=</span><var>mpcinstalldir</var></samp>&rsquo;).  The
   1038  1.1  mrg <samp><span class="option">--with-gmp=</span><var>gmpinstalldir</var></samp> option is shorthand for
   1039  1.1  mrg <samp><span class="option">--with-gmp-lib=</span><var>gmpinstalldir</var><span class="option">/lib</span></samp> and
   1040  1.1  mrg <samp><span class="option">--with-gmp-include=</span><var>gmpinstalldir</var><span class="option">/include</span></samp>.  Likewise the
   1041  1.1  mrg <samp><span class="option">--with-mpfr=</span><var>mpfrinstalldir</var></samp> option is shorthand for
   1042  1.1  mrg <samp><span class="option">--with-mpfr-lib=</span><var>mpfrinstalldir</var><span class="option">/lib</span></samp> and
   1043  1.1  mrg <samp><span class="option">--with-mpfr-include=</span><var>mpfrinstalldir</var><span class="option">/include</span></samp>, also the
   1044  1.1  mrg <samp><span class="option">--with-mpc=</span><var>mpcinstalldir</var></samp> option is shorthand for
   1045  1.1  mrg <samp><span class="option">--with-mpc-lib=</span><var>mpcinstalldir</var><span class="option">/lib</span></samp> and
   1046  1.1  mrg <samp><span class="option">--with-mpc-include=</span><var>mpcinstalldir</var><span class="option">/include</span></samp>.  If these
   1047  1.1  mrg shorthand assumptions are not correct, you can use the explicit
   1048  1.3  mrg include and lib options directly.  You might also need to ensure the
   1049  1.3  mrg shared libraries can be found by the dynamic linker when building and
   1050  1.3  mrg using GCC, for example by setting the runtime shared library path
   1051  1.3  mrg variable (<samp><span class="env">LD_LIBRARY_PATH</span></samp> on GNU/Linux and Solaris systems).
   1052  1.3  mrg 
   1053  1.3  mrg      <p>These flags are applicable to the host platform only.  When building
   1054  1.3  mrg a cross compiler, they will not be used to configure target libraries.
   1055  1.1  mrg 
   1056  1.5  mrg      <br><dt><code>--with-isl=</code><var>pathname</var><dt><code>--with-isl-include=</code><var>pathname</var><dt><code>--with-isl-lib=</code><var>pathname</var><dd>If you do not have the ISL library installed in a standard location and you
   1057  1.5  mrg want to build GCC, you can explicitly specify the directory where it is
   1058  1.5  mrg installed (&lsquo;<samp><span class="samp">--with-isl=</span><var>islinstalldir</var></samp>&rsquo;). The
   1059  1.3  mrg <samp><span class="option">--with-isl=</span><var>islinstalldir</var></samp> option is shorthand for
   1060  1.3  mrg <samp><span class="option">--with-isl-lib=</span><var>islinstalldir</var><span class="option">/lib</span></samp> and
   1061  1.5  mrg <samp><span class="option">--with-isl-include=</span><var>islinstalldir</var><span class="option">/include</span></samp>. If this
   1062  1.5  mrg shorthand assumption is not correct, you can use the explicit
   1063  1.1  mrg include and lib options directly.
   1064  1.1  mrg 
   1065  1.3  mrg      <p>These flags are applicable to the host platform only.  When building
   1066  1.3  mrg a cross compiler, they will not be used to configure target libraries.
   1067  1.3  mrg 
   1068  1.1  mrg      <br><dt><code>--with-host-libstdcxx=</code><var>linker-args</var><dd>If you are linking with a static copy of PPL, you can use this option
   1069  1.1  mrg to specify how the linker should find the standard C++ library used
   1070  1.1  mrg internally by PPL.  Typical values of <var>linker-args</var> might be
   1071  1.1  mrg &lsquo;<samp><span class="samp">-lstdc++</span></samp>&rsquo; or &lsquo;<samp><span class="samp">-Wl,-Bstatic,-lstdc++,-Bdynamic -lm</span></samp>&rsquo;.  If you are
   1072  1.1  mrg linking with a shared copy of PPL, you probably do not need this
   1073  1.1  mrg option; shared library dependencies will cause the linker to search
   1074  1.1  mrg for the standard C++ library automatically.
   1075  1.1  mrg 
   1076  1.1  mrg      <br><dt><code>--with-stage1-ldflags=</code><var>flags</var><dd>This option may be used to set linker flags to be used when linking
   1077  1.1  mrg stage 1 of GCC.  These are also used when linking GCC if configured with
   1078  1.1  mrg <samp><span class="option">--disable-bootstrap</span></samp>.  By default no special flags are used.
   1079  1.1  mrg 
   1080  1.1  mrg      <br><dt><code>--with-stage1-libs=</code><var>libs</var><dd>This option may be used to set libraries to be used when linking stage 1
   1081  1.1  mrg of GCC.  These are also used when linking GCC if configured with
   1082  1.1  mrg <samp><span class="option">--disable-bootstrap</span></samp>.  The default is the argument to
   1083  1.1  mrg <samp><span class="option">--with-host-libstdcxx</span></samp>, if specified.
   1084  1.1  mrg 
   1085  1.1  mrg      <br><dt><code>--with-boot-ldflags=</code><var>flags</var><dd>This option may be used to set linker flags to be used when linking
   1086  1.3  mrg stage 2 and later when bootstrapping GCC.  If neither &ndash;with-boot-libs
   1087  1.3  mrg nor &ndash;with-host-libstdcxx is set to a value, then the default is
   1088  1.3  mrg &lsquo;<samp><span class="samp">-static-libstdc++ -static-libgcc</span></samp>&rsquo;.
   1089  1.1  mrg 
   1090  1.1  mrg      <br><dt><code>--with-boot-libs=</code><var>libs</var><dd>This option may be used to set libraries to be used when linking stage 2
   1091  1.1  mrg and later when bootstrapping GCC.  The default is the argument to
   1092  1.1  mrg <samp><span class="option">--with-host-libstdcxx</span></samp>, if specified.
   1093  1.1  mrg 
   1094  1.1  mrg      <br><dt><code>--with-debug-prefix-map=</code><var>map</var><dd>Convert source directory names using <samp><span class="option">-fdebug-prefix-map</span></samp> when
   1095  1.1  mrg building runtime libraries.  &lsquo;<samp><var>map</var></samp>&rsquo; is a space-separated
   1096  1.1  mrg list of maps of the form &lsquo;<samp><var>old</var><span class="samp">=</span><var>new</var></samp>&rsquo;.
   1097  1.1  mrg 
   1098  1.1  mrg      <br><dt><code>--enable-linker-build-id</code><dd>Tells GCC to pass <samp><span class="option">--build-id</span></samp> option to the linker for all final
   1099  1.1  mrg links (links performed without the <samp><span class="option">-r</span></samp> or <samp><span class="option">--relocatable</span></samp>
   1100  1.1  mrg option), if the linker supports it.  If you specify
   1101  1.1  mrg <samp><span class="option">--enable-linker-build-id</span></samp>, but your linker does not
   1102  1.1  mrg support <samp><span class="option">--build-id</span></samp> option, a warning is issued and the
   1103  1.1  mrg <samp><span class="option">--enable-linker-build-id</span></samp> option is ignored.  The default is off.
   1104  1.1  mrg 
   1105  1.3  mrg      <br><dt><code>--with-linker-hash-style=</code><var>choice</var><dd>Tells GCC to pass <samp><span class="option">--hash-style=</span><var>choice</var></samp> option to the
   1106  1.3  mrg linker for all final links. <var>choice</var> can be one of
   1107  1.3  mrg &lsquo;<samp><span class="samp">sysv</span></samp>&rsquo;, &lsquo;<samp><span class="samp">gnu</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">both</span></samp>&rsquo; where &lsquo;<samp><span class="samp">sysv</span></samp>&rsquo; is the default.
   1108  1.3  mrg 
   1109  1.1  mrg      <br><dt><code>--enable-gnu-unique-object</code><dt><code>--disable-gnu-unique-object</code><dd>Tells GCC to use the gnu_unique_object relocation for C++ template
   1110  1.1  mrg static data members and inline function local statics.  Enabled by
   1111  1.5  mrg default for a toolchain with an assembler that accepts it and
   1112  1.1  mrg GLIBC 2.11 or above, otherwise disabled.
   1113  1.1  mrg 
   1114  1.5  mrg      <br><dt><code>--with-diagnostics-color=</code><var>choice</var><dd>Tells GCC to use <var>choice</var> as the default for <samp><span class="option">-fdiagnostics-color=</span></samp>
   1115  1.5  mrg option (if not used explicitly on the command line).  <var>choice</var>
   1116  1.5  mrg can be one of &lsquo;<samp><span class="samp">never</span></samp>&rsquo;, &lsquo;<samp><span class="samp">auto</span></samp>&rsquo;, &lsquo;<samp><span class="samp">always</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">auto-if-env</span></samp>&rsquo;
   1117  1.5  mrg where &lsquo;<samp><span class="samp">auto</span></samp>&rsquo; is the default.  &lsquo;<samp><span class="samp">auto-if-env</span></samp>&rsquo; means that
   1118  1.5  mrg <samp><span class="option">-fdiagnostics-color=auto</span></samp> will be the default if <code>GCC_COLORS</code>
   1119  1.5  mrg is present and non-empty in the environment, and
   1120  1.5  mrg <samp><span class="option">-fdiagnostics-color=never</span></samp> otherwise.
   1121  1.5  mrg 
   1122  1.3  mrg      <br><dt><code>--enable-lto</code><dt><code>--disable-lto</code><dd>Enable support for link-time optimization (LTO).  This is enabled by
   1123  1.3  mrg default, and may be disabled using <samp><span class="option">--disable-lto</span></samp>.
   1124  1.3  mrg 
   1125  1.5  mrg      <br><dt><code>--enable-linker-plugin-configure-flags=FLAGS</code><dt><code>--enable-linker-plugin-flags=FLAGS</code><dd>By default, linker plugins (such as the LTO plugin) are built for the
   1126  1.5  mrg host system architecture.  For the case that the linker has a
   1127  1.5  mrg different (but run-time compatible) architecture, these flags can be
   1128  1.5  mrg specified to build plugins that are compatible to the linker.  For
   1129  1.5  mrg example, if you are building GCC for a 64-bit x86_64
   1130  1.5  mrg (&lsquo;<samp><span class="samp">x86_64-unknown-linux-gnu</span></samp>&rsquo;) host system, but have a 32-bit x86
   1131  1.5  mrg GNU/Linux (&lsquo;<samp><span class="samp">i686-pc-linux-gnu</span></samp>&rsquo;) linker executable (which is
   1132  1.5  mrg executable on the former system), you can configure GCC as follows for
   1133  1.5  mrg getting compatible linker plugins:
   1134  1.5  mrg 
   1135  1.5  mrg      <pre class="smallexample">          % <var>srcdir</var>/configure \
   1136  1.5  mrg               --host=x86_64-unknown-linux-gnu \
   1137  1.5  mrg               --enable-linker-plugin-configure-flags=--host=i686-pc-linux-gnu \
   1138  1.5  mrg               --enable-linker-plugin-flags='CC=gcc\ -m32\ -Wl,-rpath,[...]/i686-pc-linux-gnu/lib'
   1139  1.5  mrg </pre>
   1140  1.3  mrg      <br><dt><code>--with-plugin-ld=</code><var>pathname</var><dd>Enable an alternate linker to be used at link-time optimization (LTO)
   1141  1.3  mrg link time when <samp><span class="option">-fuse-linker-plugin</span></samp> is enabled. 
   1142  1.3  mrg This linker should have plugin support such as gold starting with
   1143  1.3  mrg version 2.20 or GNU ld starting with version 2.21. 
   1144  1.3  mrg See <samp><span class="option">-fuse-linker-plugin</span></samp> for details.
   1145  1.3  mrg 
   1146  1.3  mrg      <br><dt><code>--enable-canonical-system-headers</code><dt><code>--disable-canonical-system-headers</code><dd>Enable system header path canonicalization for <samp><span class="file">libcpp</span></samp>.  This can
   1147  1.3  mrg produce shorter header file paths in diagnostics and dependency output
   1148  1.3  mrg files, but these changed header paths may conflict with some compilation
   1149  1.3  mrg environments.  Enabled by default, and may be disabled using
   1150  1.5  mrg <samp><span class="option">--disable-canonical-system-headers</span></samp>.
   1151  1.5  mrg 
   1152  1.5  mrg      <br><dt><code>--with-glibc-version=</code><var>major</var><code>.</code><var>minor</var><dd>Tell GCC that when the GNU C Library (glibc) is used on the target it
   1153  1.5  mrg will be version <var>major</var>.<var>minor</var> or later.  Normally this can
   1154  1.5  mrg be detected from the C library's header files, but this option may be
   1155  1.5  mrg needed when bootstrapping a cross toolchain without the header files
   1156  1.5  mrg available for building the initial bootstrap compiler.
   1157  1.5  mrg 
   1158  1.5  mrg      <p>If GCC is configured with some multilibs that use glibc and some that
   1159  1.5  mrg do not, this option applies only to the multilibs that use glibc. 
   1160  1.5  mrg However, such configurations may not work well as not all the relevant
   1161  1.5  mrg configuration in GCC is on a per-multilib basis.
   1162  1.5  mrg 
   1163  1.5  mrg      <br><dt><code>--enable-as-accelerator-for=</code><var>target</var><dd>Build as offload target compiler. Specify offload host triple by <var>target</var>.
   1164  1.5  mrg 
   1165  1.5  mrg      <br><dt><code>--enable-offload-targets=</code><var>target1</var><code>[=</code><var>path1</var><code>],...,</code><var>targetN</var><code>[=</code><var>pathN</var><code>]</code><dd>Enable offloading to targets <var>target1</var>, <small class="dots">...</small>, <var>targetN</var>. 
   1166  1.5  mrg Offload compilers are expected to be already installed.  Default search
   1167  1.5  mrg path for them is <samp><var>exec-prefix</var></samp>, but it can be changed by
   1168  1.5  mrg specifying paths <var>path1</var>, <small class="dots">...</small>, <var>pathN</var>.
   1169  1.5  mrg 
   1170  1.5  mrg      <pre class="smallexample">          % <var>srcdir</var>/configure \
   1171  1.5  mrg               --enable-offload-target=i686-unknown-linux-gnu=/path/to/i686/compiler,x86_64-pc-linux-gnu
   1172  1.5  mrg </pre>
   1173  1.5  mrg      </dl>
   1174  1.1  mrg 
   1175  1.1  mrg <h4 class="subheading"><a name="TOC3"></a>Cross-Compiler-Specific Options</h4>
   1176  1.1  mrg 
   1177  1.1  mrg <p>The following options only apply to building cross compilers.
   1178  1.1  mrg 
   1179  1.1  mrg      <dl>
   1180  1.3  mrg <dt><code>--with-sysroot</code><dt><code>--with-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the root of a tree that contains
   1181  1.3  mrg (a subset of) the root filesystem of the target operating system. 
   1182  1.1  mrg Target system headers, libraries and run-time object files will be
   1183  1.3  mrg searched for in there.  More specifically, this acts as if
   1184  1.1  mrg <samp><span class="option">--sysroot=</span><var>dir</var></samp> was added to the default options of the built
   1185  1.1  mrg compiler.  The specified directory is not copied into the
   1186  1.1  mrg install tree, unlike the options <samp><span class="option">--with-headers</span></samp> and
   1187  1.1  mrg <samp><span class="option">--with-libs</span></samp> that this option obsoletes.  The default value,
   1188  1.1  mrg in case <samp><span class="option">--with-sysroot</span></samp> is not given an argument, is
   1189  1.1  mrg <samp><span class="option">${gcc_tooldir}/sys-root</span></samp>.  If the specified directory is a
   1190  1.1  mrg subdirectory of <samp><span class="option">${exec_prefix}</span></samp>, then it will be found relative to
   1191  1.1  mrg the GCC binaries if the installation tree is moved.
   1192  1.1  mrg 
   1193  1.1  mrg      <p>This option affects the system root for the compiler used to build
   1194  1.1  mrg target libraries (which runs on the build system) and the compiler newly
   1195  1.1  mrg installed with <code>make install</code>; it does not affect the compiler which is
   1196  1.1  mrg used to build GCC itself.
   1197  1.1  mrg 
   1198  1.3  mrg      <p>If you specify the <samp><span class="option">--with-native-system-header-dir=</span><var>dirname</var></samp>
   1199  1.3  mrg option then the compiler will search that directory within <var>dirname</var> for
   1200  1.3  mrg native system headers rather than the default <samp><span class="file">/usr/include</span></samp>.
   1201  1.3  mrg 
   1202  1.1  mrg      <br><dt><code>--with-build-sysroot</code><dt><code>--with-build-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the system root (see
   1203  1.1  mrg <samp><span class="option">--with-sysroot</span></samp>) while building target libraries, instead of
   1204  1.1  mrg the directory specified with <samp><span class="option">--with-sysroot</span></samp>.  This option is
   1205  1.1  mrg only useful when you are already using <samp><span class="option">--with-sysroot</span></samp>.  You
   1206  1.1  mrg can use <samp><span class="option">--with-build-sysroot</span></samp> when you are configuring with
   1207  1.1  mrg <samp><span class="option">--prefix</span></samp> set to a directory that is different from the one in
   1208  1.1  mrg which you are installing GCC and your target libraries.
   1209  1.1  mrg 
   1210  1.1  mrg      <p>This option affects the system root for the compiler used to build
   1211  1.1  mrg target libraries (which runs on the build system); it does not affect
   1212  1.1  mrg the compiler which is used to build GCC itself.
   1213  1.1  mrg 
   1214  1.3  mrg      <p>If you specify the <samp><span class="option">--with-native-system-header-dir=</span><var>dirname</var></samp>
   1215  1.3  mrg option then the compiler will search that directory within <var>dirname</var> for
   1216  1.3  mrg native system headers rather than the default <samp><span class="file">/usr/include</span></samp>.
   1217  1.3  mrg 
   1218  1.1  mrg      <br><dt><code>--with-headers</code><dt><code>--with-headers=</code><var>dir</var><dd>Deprecated in favor of <samp><span class="option">--with-sysroot</span></samp>. 
   1219  1.1  mrg Specifies that target headers are available when building a cross compiler. 
   1220  1.1  mrg The <var>dir</var> argument specifies a directory which has the target include
   1221  1.1  mrg files.  These include files will be copied into the <samp><span class="file">gcc</span></samp> install
   1222  1.1  mrg directory.  <em>This option with the </em><var>dir</var><em> argument is required</em> when
   1223  1.1  mrg building a cross compiler, if <samp><var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span></samp>
   1224  1.1  mrg doesn't pre-exist.  If <samp><var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span></samp> does
   1225  1.1  mrg pre-exist, the <var>dir</var> argument may be omitted.  <samp><span class="command">fixincludes</span></samp>
   1226  1.1  mrg will be run on these files to make them compatible with GCC.
   1227  1.1  mrg 
   1228  1.1  mrg      <br><dt><code>--without-headers</code><dd>Tells GCC not use any target headers from a libc when building a cross
   1229  1.1  mrg compiler.  When crossing to GNU/Linux, you need the headers so GCC
   1230  1.1  mrg can build the exception handling for libgcc.
   1231  1.1  mrg 
   1232  1.1  mrg      <br><dt><code>--with-libs</code><dt><code>--with-libs="</code><var>dir1</var> <var>dir2</var><code> ... </code><var>dirN</var><code>"</code><dd>Deprecated in favor of <samp><span class="option">--with-sysroot</span></samp>. 
   1233  1.1  mrg Specifies a list of directories which contain the target runtime
   1234  1.1  mrg libraries.  These libraries will be copied into the <samp><span class="file">gcc</span></samp> install
   1235  1.1  mrg directory.  If the directory list is omitted, this option has no
   1236  1.1  mrg effect.
   1237  1.1  mrg 
   1238  1.1  mrg      <br><dt><code>--with-newlib</code><dd>Specifies that &lsquo;<samp><span class="samp">newlib</span></samp>&rsquo; is
   1239  1.1  mrg being used as the target C library.  This causes <code>__eprintf</code> to be
   1240  1.1  mrg omitted from <samp><span class="file">libgcc.a</span></samp> on the assumption that it will be provided by
   1241  1.1  mrg &lsquo;<samp><span class="samp">newlib</span></samp>&rsquo;.
   1242  1.1  mrg 
   1243  1.3  mrg      <br><dt><code>--with-avrlibc</code><dd>Specifies that &lsquo;<samp><span class="samp">AVR-Libc</span></samp>&rsquo; is
   1244  1.3  mrg being used as the target C library.  This causes float support
   1245  1.3  mrg functions like <code>__addsf3</code> to be omitted from <samp><span class="file">libgcc.a</span></samp> on
   1246  1.3  mrg the assumption that it will be provided by <samp><span class="file">libm.a</span></samp>.  For more
   1247  1.3  mrg technical details, cf. <a href="http://gcc.gnu.org/PR54461">PR54461</a>. 
   1248  1.3  mrg This option is only supported for the AVR target.  It is not supported for
   1249  1.3  mrg RTEMS configurations, which currently use newlib.  The option is
   1250  1.3  mrg supported since version 4.7.2 and is the default in 4.8.0 and newer.
   1251  1.3  mrg 
   1252  1.5  mrg      <br><dt><code>--with-nds32-lib=</code><var>library</var><dd>Specifies that <var>library</var> setting is used for building <samp><span class="file">libgcc.a</span></samp>. 
   1253  1.5  mrg Currently, the valid <var>library</var> is &lsquo;<samp><span class="samp">newlib</span></samp>&rsquo; or &lsquo;<samp><span class="samp">mculib</span></samp>&rsquo;. 
   1254  1.5  mrg This option is only supported for the NDS32 target.
   1255  1.5  mrg 
   1256  1.1  mrg      <br><dt><code>--with-build-time-tools=</code><var>dir</var><dd>Specifies where to find the set of target tools (assembler, linker, etc.) 
   1257  1.1  mrg that will be used while building GCC itself.  This option can be useful
   1258  1.1  mrg if the directory layouts are different between the system you are building
   1259  1.1  mrg GCC on, and the system where you will deploy it.
   1260  1.1  mrg 
   1261  1.1  mrg      <p>For example, on an &lsquo;<samp><span class="samp">ia64-hp-hpux</span></samp>&rsquo; system, you may have the GNU
   1262  1.1  mrg assembler and linker in <samp><span class="file">/usr/bin</span></samp>, and the native tools in a
   1263  1.1  mrg different path, and build a toolchain that expects to find the
   1264  1.1  mrg native tools in <samp><span class="file">/usr/bin</span></samp>.
   1265  1.1  mrg 
   1266  1.1  mrg      <p>When you use this option, you should ensure that <var>dir</var> includes
   1267  1.1  mrg <samp><span class="command">ar</span></samp>, <samp><span class="command">as</span></samp>, <samp><span class="command">ld</span></samp>, <samp><span class="command">nm</span></samp>,
   1268  1.1  mrg <samp><span class="command">ranlib</span></samp> and <samp><span class="command">strip</span></samp> if necessary, and possibly
   1269  1.1  mrg <samp><span class="command">objdump</span></samp>.  Otherwise, GCC may use an inconsistent set of
   1270  1.1  mrg tools. 
   1271  1.1  mrg </dl>
   1272  1.1  mrg 
   1273  1.1  mrg <h4 class="subheading"><a name="TOC4"></a>Java-Specific Options</h4>
   1274  1.1  mrg 
   1275  1.1  mrg <p>The following option applies to the build of the Java front end.
   1276  1.1  mrg 
   1277  1.1  mrg      <dl>
   1278  1.1  mrg <dt><code>--disable-libgcj</code><dd>Specify that the run-time libraries
   1279  1.1  mrg used by GCJ should not be built.  This is useful in case you intend
   1280  1.1  mrg to use GCJ with some other run-time, or you're going to install it
   1281  1.1  mrg separately, or it just happens not to build on your particular
   1282  1.1  mrg machine.  In general, if the Java front end is enabled, the GCJ
   1283  1.1  mrg libraries will be enabled too, unless they're known to not work on
   1284  1.1  mrg the target platform.  If GCJ is enabled but &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo; isn't built, you
   1285  1.1  mrg may need to port it; in this case, before modifying the top-level
   1286  1.1  mrg <samp><span class="file">configure.in</span></samp> so that &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo; is enabled by default on this platform,
   1287  1.1  mrg you may use <samp><span class="option">--enable-libgcj</span></samp> to override the default.
   1288  1.1  mrg 
   1289  1.1  mrg    </dl>
   1290  1.1  mrg 
   1291  1.1  mrg    <p>The following options apply to building &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo;.
   1292  1.1  mrg 
   1293  1.1  mrg <h5 class="subsubheading"><a name="TOC5"></a>General Options</h5>
   1294  1.1  mrg 
   1295  1.1  mrg      <dl>
   1296  1.1  mrg <dt><code>--enable-java-maintainer-mode</code><dd>By default the &lsquo;<samp><span class="samp">libjava</span></samp>&rsquo; build will not attempt to compile the
   1297  1.1  mrg <samp><span class="file">.java</span></samp> source files to <samp><span class="file">.class</span></samp>.  Instead, it will use the
   1298  1.1  mrg <samp><span class="file">.class</span></samp> files from the source tree.  If you use this option you
   1299  1.1  mrg must have executables named <samp><span class="command">ecj1</span></samp> and <samp><span class="command">gjavah</span></samp> in your path
   1300  1.1  mrg for use by the build.  You must use this option if you intend to
   1301  1.1  mrg modify any <samp><span class="file">.java</span></samp> files in <samp><span class="file">libjava</span></samp>.
   1302  1.1  mrg 
   1303  1.1  mrg      <br><dt><code>--with-java-home=</code><var>dirname</var><dd>This &lsquo;<samp><span class="samp">libjava</span></samp>&rsquo; option overrides the default value of the
   1304  1.1  mrg &lsquo;<samp><span class="samp">java.home</span></samp>&rsquo; system property.  It is also used to set
   1305  1.1  mrg &lsquo;<samp><span class="samp">sun.boot.class.path</span></samp>&rsquo; to <samp><var>dirname</var><span class="file">/lib/rt.jar</span></samp>.  By
   1306  1.1  mrg default &lsquo;<samp><span class="samp">java.home</span></samp>&rsquo; is set to <samp><var>prefix</var></samp> and
   1307  1.1  mrg &lsquo;<samp><span class="samp">sun.boot.class.path</span></samp>&rsquo; to
   1308  1.1  mrg <samp><var>datadir</var><span class="file">/java/libgcj-</span><var>version</var><span class="file">.jar</span></samp>.
   1309  1.1  mrg 
   1310  1.1  mrg      <br><dt><code>--with-ecj-jar=</code><var>filename</var><dd>This option can be used to specify the location of an external jar
   1311  1.1  mrg file containing the Eclipse Java compiler.  A specially modified
   1312  1.1  mrg version of this compiler is used by <samp><span class="command">gcj</span></samp> to parse
   1313  1.1  mrg <samp><span class="file">.java</span></samp> source files.  If this option is given, the
   1314  1.1  mrg &lsquo;<samp><span class="samp">libjava</span></samp>&rsquo; build will create and install an <samp><span class="file">ecj1</span></samp> executable
   1315  1.1  mrg which uses this jar file at runtime.
   1316  1.1  mrg 
   1317  1.1  mrg      <p>If this option is not given, but an <samp><span class="file">ecj.jar</span></samp> file is found in
   1318  1.1  mrg the topmost source tree at configure time, then the &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo;
   1319  1.1  mrg build will create and install <samp><span class="file">ecj1</span></samp>, and will also install the
   1320  1.1  mrg discovered <samp><span class="file">ecj.jar</span></samp> into a suitable place in the install tree.
   1321  1.1  mrg 
   1322  1.1  mrg      <p>If <samp><span class="file">ecj1</span></samp> is not installed, then the user will have to supply one
   1323  1.1  mrg on his path in order for <samp><span class="command">gcj</span></samp> to properly parse <samp><span class="file">.java</span></samp>
   1324  1.1  mrg source files.  A suitable jar is available from
   1325  1.1  mrg <a href="ftp://sourceware.org/pub/java/">ftp://sourceware.org/pub/java/</a>.
   1326  1.1  mrg 
   1327  1.1  mrg      <br><dt><code>--disable-getenv-properties</code><dd>Don't set system properties from <samp><span class="env">GCJ_PROPERTIES</span></samp>.
   1328  1.1  mrg 
   1329  1.1  mrg      <br><dt><code>--enable-hash-synchronization</code><dd>Use a global hash table for monitor locks.  Ordinarily,
   1330  1.1  mrg &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo;'s &lsquo;<samp><span class="samp">configure</span></samp>&rsquo; script automatically makes
   1331  1.1  mrg the correct choice for this option for your platform.  Only use
   1332  1.1  mrg this if you know you need the library to be configured differently.
   1333  1.1  mrg 
   1334  1.1  mrg      <br><dt><code>--enable-interpreter</code><dd>Enable the Java interpreter.  The interpreter is automatically
   1335  1.1  mrg enabled by default on all platforms that support it.  This option
   1336  1.1  mrg is really only useful if you want to disable the interpreter
   1337  1.1  mrg (using <samp><span class="option">--disable-interpreter</span></samp>).
   1338  1.1  mrg 
   1339  1.1  mrg      <br><dt><code>--disable-java-net</code><dd>Disable java.net.  This disables the native part of java.net only,
   1340  1.1  mrg using non-functional stubs for native method implementations.
   1341  1.1  mrg 
   1342  1.1  mrg      <br><dt><code>--disable-jvmpi</code><dd>Disable JVMPI support.
   1343  1.1  mrg 
   1344  1.1  mrg      <br><dt><code>--disable-libgcj-bc</code><dd>Disable BC ABI compilation of certain parts of libgcj.  By default,
   1345  1.1  mrg some portions of libgcj are compiled with <samp><span class="option">-findirect-dispatch</span></samp>
   1346  1.1  mrg and <samp><span class="option">-fno-indirect-classes</span></samp>, allowing them to be overridden at
   1347  1.1  mrg run-time.
   1348  1.1  mrg 
   1349  1.1  mrg      <p>If <samp><span class="option">--disable-libgcj-bc</span></samp> is specified, libgcj is built without
   1350  1.1  mrg these options.  This allows the compile-time linker to resolve
   1351  1.1  mrg dependencies when statically linking to libgcj.  However it makes it
   1352  1.1  mrg impossible to override the affected portions of libgcj at run-time.
   1353  1.1  mrg 
   1354  1.1  mrg      <br><dt><code>--enable-reduced-reflection</code><dd>Build most of libgcj with <samp><span class="option">-freduced-reflection</span></samp>.  This reduces
   1355  1.1  mrg the size of libgcj at the expense of not being able to do accurate
   1356  1.1  mrg reflection on the classes it contains.  This option is safe if you
   1357  1.1  mrg know that code using libgcj will never use reflection on the standard
   1358  1.1  mrg runtime classes in libgcj (including using serialization, RMI or CORBA).
   1359  1.1  mrg 
   1360  1.1  mrg      <br><dt><code>--with-ecos</code><dd>Enable runtime eCos target support.
   1361  1.1  mrg 
   1362  1.1  mrg      <br><dt><code>--without-libffi</code><dd>Don't use &lsquo;<samp><span class="samp">libffi</span></samp>&rsquo;.  This will disable the interpreter and JNI
   1363  1.1  mrg support as well, as these require &lsquo;<samp><span class="samp">libffi</span></samp>&rsquo; to work.
   1364  1.1  mrg 
   1365  1.1  mrg      <br><dt><code>--enable-libgcj-debug</code><dd>Enable runtime debugging code.
   1366  1.1  mrg 
   1367  1.1  mrg      <br><dt><code>--enable-libgcj-multifile</code><dd>If specified, causes all <samp><span class="file">.java</span></samp> source files to be
   1368  1.1  mrg compiled into <samp><span class="file">.class</span></samp> files in one invocation of
   1369  1.1  mrg &lsquo;<samp><span class="samp">gcj</span></samp>&rsquo;.  This can speed up build time, but is more
   1370  1.1  mrg resource-intensive.  If this option is unspecified or
   1371  1.1  mrg disabled, &lsquo;<samp><span class="samp">gcj</span></samp>&rsquo; is invoked once for each <samp><span class="file">.java</span></samp>
   1372  1.1  mrg file to compile into a <samp><span class="file">.class</span></samp> file.
   1373  1.1  mrg 
   1374  1.1  mrg      <br><dt><code>--with-libiconv-prefix=DIR</code><dd>Search for libiconv in <samp><span class="file">DIR/include</span></samp> and <samp><span class="file">DIR/lib</span></samp>.
   1375  1.1  mrg 
   1376  1.1  mrg      <br><dt><code>--enable-sjlj-exceptions</code><dd>Force use of the <code>setjmp</code>/<code>longjmp</code>-based scheme for exceptions. 
   1377  1.1  mrg &lsquo;<samp><span class="samp">configure</span></samp>&rsquo; ordinarily picks the correct value based on the platform. 
   1378  1.1  mrg Only use this option if you are sure you need a different setting.
   1379  1.1  mrg 
   1380  1.1  mrg      <br><dt><code>--with-system-zlib</code><dd>Use installed &lsquo;<samp><span class="samp">zlib</span></samp>&rsquo; rather than that included with GCC.
   1381  1.1  mrg 
   1382  1.1  mrg      <br><dt><code>--with-win32-nlsapi=ansi, unicows or unicode</code><dd>Indicates how MinGW &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo; translates between UNICODE
   1383  1.1  mrg characters and the Win32 API.
   1384  1.1  mrg 
   1385  1.1  mrg      <br><dt><code>--enable-java-home</code><dd>If enabled, this creates a JPackage compatible SDK environment during install. 
   1386  1.1  mrg Note that if &ndash;enable-java-home is used, &ndash;with-arch-directory=ARCH must also
   1387  1.1  mrg be specified.
   1388  1.1  mrg 
   1389  1.1  mrg      <br><dt><code>--with-arch-directory=ARCH</code><dd>Specifies the name to use for the <samp><span class="file">jre/lib/ARCH</span></samp> directory in the SDK
   1390  1.1  mrg environment created when &ndash;enable-java-home is passed. Typical names for this
   1391  1.1  mrg directory include i386, amd64, ia64, etc.
   1392  1.1  mrg 
   1393  1.1  mrg      <br><dt><code>--with-os-directory=DIR</code><dd>Specifies the OS directory for the SDK include directory. This is set to auto
   1394  1.1  mrg detect, and is typically 'linux'.
   1395  1.1  mrg 
   1396  1.1  mrg      <br><dt><code>--with-origin-name=NAME</code><dd>Specifies the JPackage origin name. This defaults to the 'gcj' in
   1397  1.1  mrg java-1.5.0-gcj.
   1398  1.1  mrg 
   1399  1.1  mrg      <br><dt><code>--with-arch-suffix=SUFFIX</code><dd>Specifies the suffix for the sdk directory. Defaults to the empty string. 
   1400  1.1  mrg Examples include '.x86_64' in 'java-1.5.0-gcj-1.5.0.0.x86_64'.
   1401  1.1  mrg 
   1402  1.1  mrg      <br><dt><code>--with-jvm-root-dir=DIR</code><dd>Specifies where to install the SDK. Default is $(prefix)/lib/jvm.
   1403  1.1  mrg 
   1404  1.1  mrg      <br><dt><code>--with-jvm-jar-dir=DIR</code><dd>Specifies where to install jars. Default is $(prefix)/lib/jvm-exports.
   1405  1.1  mrg 
   1406  1.1  mrg      <br><dt><code>--with-python-dir=DIR</code><dd>Specifies where to install the Python modules used for aot-compile. DIR should
   1407  1.1  mrg not include the prefix used in installation. For example, if the Python modules
   1408  1.1  mrg are to be installed in /usr/lib/python2.5/site-packages, then
   1409  1.1  mrg &ndash;with-python-dir=/lib/python2.5/site-packages should be passed. If this is
   1410  1.1  mrg not specified, then the Python modules are installed in $(prefix)/share/python.
   1411  1.1  mrg 
   1412  1.1  mrg      <br><dt><code>--enable-aot-compile-rpm</code><dd>Adds aot-compile-rpm to the list of installed scripts.
   1413  1.1  mrg 
   1414  1.1  mrg      <br><dt><code>--enable-browser-plugin</code><dd>Build the gcjwebplugin web browser plugin.
   1415  1.1  mrg 
   1416  1.3  mrg      <br><dt><code>--enable-static-libjava</code><dd>Build static libraries in libjava. The default is to only build shared
   1417  1.3  mrg libraries.
   1418  1.3  mrg 
   1419  1.1  mrg           <dl>
   1420  1.1  mrg <dt><code>ansi</code><dd>Use the single-byte <code>char</code> and the Win32 A functions natively,
   1421  1.1  mrg translating to and from UNICODE when using these functions.  If
   1422  1.1  mrg unspecified, this is the default.
   1423  1.1  mrg 
   1424  1.1  mrg           <br><dt><code>unicows</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively.  Adds
   1425  1.1  mrg <code>-lunicows</code> to <samp><span class="file">libgcj.spec</span></samp> to link with &lsquo;<samp><span class="samp">libunicows</span></samp>&rsquo;. 
   1426  1.1  mrg <samp><span class="file">unicows.dll</span></samp> needs to be deployed on Microsoft Windows 9X machines
   1427  1.1  mrg running built executables.  <samp><span class="file">libunicows.a</span></samp>, an open-source
   1428  1.1  mrg import library around Microsoft's <code>unicows.dll</code>, is obtained from
   1429  1.1  mrg <a href="http://libunicows.sourceforge.net/">http://libunicows.sourceforge.net/</a>, which also gives details
   1430  1.1  mrg on getting <samp><span class="file">unicows.dll</span></samp> from Microsoft.
   1431  1.1  mrg 
   1432  1.1  mrg           <br><dt><code>unicode</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively.  Does <em>not</em>
   1433  1.1  mrg add <code>-lunicows</code> to <samp><span class="file">libgcj.spec</span></samp>.  The built executables will
   1434  1.1  mrg only run on Microsoft Windows NT and above. 
   1435  1.1  mrg </dl>
   1436  1.1  mrg      </dl>
   1437  1.1  mrg 
   1438  1.1  mrg <h5 class="subsubheading"><a name="TOC6"></a>AWT-Specific Options</h5>
   1439  1.1  mrg 
   1440  1.1  mrg      <dl>
   1441  1.1  mrg <dt><code>--with-x</code><dd>Use the X Window System.
   1442  1.1  mrg 
   1443  1.1  mrg      <br><dt><code>--enable-java-awt=PEER(S)</code><dd>Specifies the AWT peer library or libraries to build alongside
   1444  1.1  mrg &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo;.  If this option is unspecified or disabled, AWT
   1445  1.1  mrg will be non-functional.  Current valid values are <samp><span class="option">gtk</span></samp> and
   1446  1.1  mrg <samp><span class="option">xlib</span></samp>.  Multiple libraries should be separated by a
   1447  1.1  mrg comma (i.e. <samp><span class="option">--enable-java-awt=gtk,xlib</span></samp>).
   1448  1.1  mrg 
   1449  1.1  mrg      <br><dt><code>--enable-gtk-cairo</code><dd>Build the cairo Graphics2D implementation on GTK.
   1450  1.1  mrg 
   1451  1.1  mrg      <br><dt><code>--enable-java-gc=TYPE</code><dd>Choose garbage collector.  Defaults to <samp><span class="option">boehm</span></samp> if unspecified.
   1452  1.1  mrg 
   1453  1.1  mrg      <br><dt><code>--disable-gtktest</code><dd>Do not try to compile and run a test GTK+ program.
   1454  1.1  mrg 
   1455  1.1  mrg      <br><dt><code>--disable-glibtest</code><dd>Do not try to compile and run a test GLIB program.
   1456  1.1  mrg 
   1457  1.1  mrg      <br><dt><code>--with-libart-prefix=PFX</code><dd>Prefix where libart is installed (optional).
   1458  1.1  mrg 
   1459  1.1  mrg      <br><dt><code>--with-libart-exec-prefix=PFX</code><dd>Exec prefix where libart is installed (optional).
   1460  1.1  mrg 
   1461  1.1  mrg      <br><dt><code>--disable-libarttest</code><dd>Do not try to compile and run a test libart program.
   1462  1.1  mrg 
   1463  1.1  mrg </dl>
   1464  1.1  mrg 
   1465  1.3  mrg <h5 class="subsubheading"><a name="TOC7"></a>Overriding <samp><span class="command">configure</span></samp> test results</h5>
   1466  1.3  mrg 
   1467  1.3  mrg <p>Sometimes, it might be necessary to override the result of some
   1468  1.3  mrg <samp><span class="command">configure</span></samp> test, for example in order to ease porting to a new
   1469  1.3  mrg system or work around a bug in a test.  The toplevel <samp><span class="command">configure</span></samp>
   1470  1.3  mrg script provides three variables for this:
   1471  1.3  mrg 
   1472  1.3  mrg      <dl>
   1473  1.3  mrg <dt><code>build_configargs</code><dd><a name="index-g_t_0040code_007bbuild_005fconfigargs_007d-3"></a>The contents of this variable is passed to all build <samp><span class="command">configure</span></samp>
   1474  1.3  mrg scripts.
   1475  1.3  mrg 
   1476  1.3  mrg      <br><dt><code>host_configargs</code><dd><a name="index-g_t_0040code_007bhost_005fconfigargs_007d-4"></a>The contents of this variable is passed to all host <samp><span class="command">configure</span></samp>
   1477  1.3  mrg scripts.
   1478  1.3  mrg 
   1479  1.3  mrg      <br><dt><code>target_configargs</code><dd><a name="index-g_t_0040code_007btarget_005fconfigargs_007d-5"></a>The contents of this variable is passed to all target <samp><span class="command">configure</span></samp>
   1480  1.3  mrg scripts.
   1481  1.3  mrg 
   1482  1.3  mrg    </dl>
   1483  1.3  mrg 
   1484  1.3  mrg    <p>In order to avoid shell and <samp><span class="command">make</span></samp> quoting issues for complex
   1485  1.3  mrg overrides, you can pass a setting for <samp><span class="env">CONFIG_SITE</span></samp> and set
   1486  1.3  mrg variables in the site file.
   1487  1.3  mrg 
   1488  1.1  mrg    <p><hr />
   1489  1.1  mrg <p><a href="./index.html">Return to the GCC Installation page</a>
   1490  1.1  mrg 
   1491  1.1  mrg <!-- ***Building**************************************************************** -->
   1492  1.1  mrg <!-- ***Testing***************************************************************** -->
   1493  1.1  mrg <!-- ***Final install*********************************************************** -->
   1494  1.1  mrg <!-- ***Binaries**************************************************************** -->
   1495  1.1  mrg <!-- ***Specific**************************************************************** -->
   1496  1.1  mrg <!-- ***Old documentation****************************************************** -->
   1497  1.1  mrg <!-- ***GFDL******************************************************************** -->
   1498  1.1  mrg <!-- *************************************************************************** -->
   1499  1.1  mrg <!-- Part 6 The End of the Document -->
   1500  1.1  mrg </body></html>
   1501  1.1  mrg 
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