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1 <html lang="en"> 2 <head> 3 <title>Installing GCC: Configuration</title> 4 <meta http-equiv="Content-Type" content="text/html"> 5 <meta name="description" content="Installing GCC: Configuration"> 6 <meta name="generator" content="makeinfo 4.12"> 7 <link title="Top" rel="top" href="#Top"> 8 <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 9 <!-- 10 Copyright (C) 1988-2015 Free Software Foundation, Inc. 11 12 Permission is granted to copy, distribute and/or modify this document 13 under the terms of the GNU Free Documentation License, Version 1.3 or 14 any later version published by the Free Software Foundation; with no 15 Invariant Sections, the Front-Cover texts being (a) (see below), and 16 with the Back-Cover Texts being (b) (see below). A copy of the 17 license is included in the section entitled "GNU Free Documentation License". 18 19 (a) The FSF's Front-Cover Text is: 20 21 A GNU Manual 22 23 (b) The FSF's Back-Cover Text is: 24 25 You have freedom to copy and modify this GNU Manual, like GNU 26 software. Copies published by the Free Software Foundation raise 27 funds for GNU development.--> 28 <meta http-equiv="Content-Style-Type" content="text/css"> 29 <style type="text/css"><!-- 30 pre.display { font-family:inherit } 31 pre.format { font-family:inherit } 32 pre.smalldisplay { font-family:inherit; font-size:smaller } 33 pre.smallformat { font-family:inherit; font-size:smaller } 34 pre.smallexample { font-size:smaller } 35 pre.smalllisp { font-size:smaller } 36 span.sc { font-variant:small-caps } 37 span.roman { font-family:serif; font-weight:normal; } 38 span.sansserif { font-family:sans-serif; font-weight:normal; } 39 --></style> 40 </head> 41 <body> 42 <h1 class="settitle">Installing GCC: Configuration</h1> 43 <a name="index-Configuration-1"></a><a name="index-Installing-GCC_003a-Configuration-2"></a> 44 Like most GNU software, GCC must be configured before it can be built. 45 This document describes the recommended configuration procedure 46 for both native and cross targets. 47 48 <p>We use <var>srcdir</var> to refer to the toplevel source directory for 49 GCC; we use <var>objdir</var> to refer to the toplevel build/object directory. 50 51 <p>If you obtained the sources via SVN, <var>srcdir</var> must refer to the top 52 <samp><span class="file">gcc</span></samp> directory, the one where the <samp><span class="file">MAINTAINERS</span></samp> file can be 53 found, and not its <samp><span class="file">gcc</span></samp> subdirectory, otherwise the build will fail. 54 55 <p>If either <var>srcdir</var> or <var>objdir</var> is located on an automounted NFS 56 file system, the shell's built-in <samp><span class="command">pwd</span></samp> command will return 57 temporary pathnames. Using these can lead to various sorts of build 58 problems. To avoid this issue, set the <samp><span class="env">PWDCMD</span></samp> environment 59 variable to an automounter-aware <samp><span class="command">pwd</span></samp> command, e.g., 60 <samp><span class="command">pawd</span></samp> or ‘<samp><span class="samp">amq -w</span></samp>’, during the configuration and build 61 phases. 62 63 <p>First, we <strong>highly</strong> recommend that GCC be built into a 64 separate directory from the sources which does <strong>not</strong> reside 65 within the source tree. This is how we generally build GCC; building 66 where <var>srcdir</var> == <var>objdir</var> should still work, but doesn't 67 get extensive testing; building where <var>objdir</var> is a subdirectory 68 of <var>srcdir</var> is unsupported. 69 70 <p>If you have previously built GCC in the same directory for a 71 different target machine, do ‘<samp><span class="samp">make distclean</span></samp>’ to delete all files 72 that might be invalid. One of the files this deletes is <samp><span class="file">Makefile</span></samp>; 73 if ‘<samp><span class="samp">make distclean</span></samp>’ complains that <samp><span class="file">Makefile</span></samp> does not exist 74 or issues a message like “don't know how to make distclean” it probably 75 means that the directory is already suitably clean. However, with the 76 recommended method of building in a separate <var>objdir</var>, you should 77 simply use a different <var>objdir</var> for each target. 78 79 <p>Second, when configuring a native system, either <samp><span class="command">cc</span></samp> or 80 <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 your environment before running configure. Otherwise the configuration 82 scripts may fail. 83 84 <p>To configure GCC: 85 86 <pre class="smallexample"> % mkdir <var>objdir</var> 87 % cd <var>objdir</var> 88 % <var>srcdir</var>/configure [<var>options</var>] [<var>target</var>] 89 </pre> 90 <h3 class="heading"><a name="TOC0"></a>Distributor options</h3> 91 92 <p>If you will be distributing binary versions of GCC, with modifications 93 to the source code, you should use the options described in this 94 section to make clear that your version contains modifications. 95 96 <dl> 97 <dt><code>--with-pkgversion=</code><var>version</var><dd>Specify a string that identifies your package. You may wish 98 to include a build number or build date. This version string will be 99 included in the output of <samp><span class="command">gcc --version</span></samp>. This suffix does 100 not replace the default version string, only the ‘<samp><span class="samp">GCC</span></samp>’ part. 101 102 <p>The default value is ‘<samp><span class="samp">GCC</span></samp>’. 103 104 <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 You are of course welcome to forward bugs reported to you to the FSF, 106 if you determine that they are not bugs in your modifications. 107 108 <p>The default value refers to the FSF's GCC bug tracker. 109 110 </dl> 111 112 <h3 class="heading"><a name="TOC1"></a>Target specification</h3> 113 114 <ul> 115 <li>GCC has code to correctly determine the correct value for <var>target</var> 116 for nearly all native systems. Therefore, we highly recommend you do 117 not provide a configure target when configuring a native compiler. 118 119 <li><var>target</var> must be specified as <samp><span class="option">--target=</span><var>target</var></samp> 120 when configuring a cross compiler; examples of valid targets would be 121 m68k-elf, sh-elf, etc. 122 123 <li>Specifying just <var>target</var> instead of <samp><span class="option">--target=</span><var>target</var></samp> 124 implies that the host defaults to <var>target</var>. 125 </ul> 126 127 <h3 class="heading"><a name="TOC2"></a>Options specification</h3> 128 129 <p>Use <var>options</var> to override several configure time options for 130 GCC. A list of supported <var>options</var> follows; ‘<samp><span class="samp">configure 131 --help</span></samp>’ may list other options, but those not listed below may not 132 work and should not normally be used. 133 134 <p>Note that each <samp><span class="option">--enable</span></samp> option has a corresponding 135 <samp><span class="option">--disable</span></samp> option and that each <samp><span class="option">--with</span></samp> option has a 136 corresponding <samp><span class="option">--without</span></samp> option. 137 138 <dl> 139 <dt><code>--prefix=</code><var>dirname</var><dd>Specify the toplevel installation 140 directory. This is the recommended way to install the tools into a directory 141 other than the default. The toplevel installation directory defaults to 142 <samp><span class="file">/usr/local</span></samp>. 143 144 <p>We <strong>highly</strong> recommend against <var>dirname</var> being the same or a 145 subdirectory of <var>objdir</var> or vice versa. If specifying a directory 146 beneath a user's home directory tree, some shells will not expand 147 <var>dirname</var> correctly if it contains the ‘<samp><span class="samp">~</span></samp>’ metacharacter; use 148 <samp><span class="env">$HOME</span></samp> instead. 149 150 <p>The following standard <samp><span class="command">autoconf</span></samp> options are supported. Normally you 151 should not need to use these options. 152 <dl> 153 <dt><code>--exec-prefix=</code><var>dirname</var><dd>Specify the toplevel installation directory for architecture-dependent 154 files. The default is <samp><var>prefix</var></samp>. 155 156 <br><dt><code>--bindir=</code><var>dirname</var><dd>Specify the installation directory for the executables called by users 157 (such as <samp><span class="command">gcc</span></samp> and <samp><span class="command">g++</span></samp>). The default is 158 <samp><var>exec-prefix</var><span class="file">/bin</span></samp>. 159 160 <br><dt><code>--libdir=</code><var>dirname</var><dd>Specify the installation directory for object code libraries and 161 internal data files of GCC. The default is <samp><var>exec-prefix</var><span class="file">/lib</span></samp>. 162 163 <br><dt><code>--libexecdir=</code><var>dirname</var><dd>Specify the installation directory for internal executables of GCC. 164 The default is <samp><var>exec-prefix</var><span class="file">/libexec</span></samp>. 165 166 <br><dt><code>--with-slibdir=</code><var>dirname</var><dd>Specify the installation directory for the shared libgcc library. The 167 default is <samp><var>libdir</var></samp>. 168 169 <br><dt><code>--datarootdir=</code><var>dirname</var><dd>Specify the root of the directory tree for read-only architecture-independent 170 data files referenced by GCC. The default is <samp><var>prefix</var><span class="file">/share</span></samp>. 171 172 <br><dt><code>--infodir=</code><var>dirname</var><dd>Specify the installation directory for documentation in info format. 173 The default is <samp><var>datarootdir</var><span class="file">/info</span></samp>. 174 175 <br><dt><code>--datadir=</code><var>dirname</var><dd>Specify the installation directory for some architecture-independent 176 data files referenced by GCC. The default is <samp><var>datarootdir</var></samp>. 177 178 <br><dt><code>--docdir=</code><var>dirname</var><dd>Specify the installation directory for documentation files (other 179 than Info) for GCC. The default is <samp><var>datarootdir</var><span class="file">/doc</span></samp>. 180 181 <br><dt><code>--htmldir=</code><var>dirname</var><dd>Specify the installation directory for HTML documentation files. 182 The default is <samp><var>docdir</var></samp>. 183 184 <br><dt><code>--pdfdir=</code><var>dirname</var><dd>Specify the installation directory for PDF documentation files. 185 The default is <samp><var>docdir</var></samp>. 186 187 <br><dt><code>--mandir=</code><var>dirname</var><dd>Specify the installation directory for manual pages. The default is 188 <samp><var>datarootdir</var><span class="file">/man</span></samp>. (Note that the manual pages are only extracts 189 from the full GCC manuals, which are provided in Texinfo format. The manpages 190 are derived by an automatic conversion process from parts of the full 191 manual.) 192 193 <br><dt><code>--with-gxx-include-dir=</code><var>dirname</var><dd>Specify 194 the installation directory for G++ header files. The default depends 195 on other configuration options, and differs between cross and native 196 configurations. 197 198 <br><dt><code>--with-specs=</code><var>specs</var><dd>Specify additional command line driver SPECS. 199 This can be useful if you need to turn on a non-standard feature by 200 default without modifying the compiler's source code, for instance 201 <samp><span class="option">--with-specs=%{!fcommon:%{!fno-common:-fno-common}}</span></samp>. 202 See “Spec Files” in the main manual 203 204 </dl> 205 206 <br><dt><code>--program-prefix=</code><var>prefix</var><dd>GCC supports some transformations of the names of its programs when 207 installing them. This option prepends <var>prefix</var> to the names of 208 programs to install in <var>bindir</var> (see above). For example, specifying 209 <samp><span class="option">--program-prefix=foo-</span></samp> would result in ‘<samp><span class="samp">gcc</span></samp>’ 210 being installed as <samp><span class="file">/usr/local/bin/foo-gcc</span></samp>. 211 212 <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 (see above). For example, specifying <samp><span class="option">--program-suffix=-3.1</span></samp> 214 would result in ‘<samp><span class="samp">gcc</span></samp>’ being installed as 215 <samp><span class="file">/usr/local/bin/gcc-3.1</span></samp>. 216 217 <br><dt><code>--program-transform-name=</code><var>pattern</var><dd>Applies the ‘<samp><span class="samp">sed</span></samp>’ script <var>pattern</var> to be applied to the names 218 of programs to install in <var>bindir</var> (see above). <var>pattern</var> has to 219 consist of one or more basic ‘<samp><span class="samp">sed</span></samp>’ editing commands, separated by 220 semicolons. For example, if you want the ‘<samp><span class="samp">gcc</span></samp>’ program name to be 221 transformed to the installed program <samp><span class="file">/usr/local/bin/myowngcc</span></samp> and 222 the ‘<samp><span class="samp">g++</span></samp>’ program name to be transformed to 223 <samp><span class="file">/usr/local/bin/gspecial++</span></samp> without changing other program names, 224 you could use the pattern 225 <samp><span class="option">--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'</span></samp> 226 to achieve this effect. 227 228 <p>All three options can be combined and used together, resulting in more 229 complex conversion patterns. As a basic rule, <var>prefix</var> (and 230 <var>suffix</var>) are prepended (appended) before further transformations 231 can happen with a special transformation script <var>pattern</var>. 232 233 <p>As currently implemented, this option only takes effect for native 234 builds; cross compiler binaries' names are not transformed even when a 235 transformation is explicitly asked for by one of these options. 236 237 <p>For native builds, some of the installed programs are also installed 238 with the target alias in front of their name, as in 239 ‘<samp><span class="samp">i686-pc-linux-gnu-gcc</span></samp>’. All of the above transformations happen 240 before the target alias is prepended to the name—so, specifying 241 <samp><span class="option">--program-prefix=foo-</span></samp> and <samp><span class="option">program-suffix=-3.1</span></samp>, the 242 resulting binary would be installed as 243 <samp><span class="file">/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1</span></samp>. 244 245 <p>As a last shortcoming, none of the installed Ada programs are 246 transformed yet, which will be fixed in some time. 247 248 <br><dt><code>--with-local-prefix=</code><var>dirname</var><dd>Specify the 249 installation directory for local include files. The default is 250 <samp><span class="file">/usr/local</span></samp>. Specify this option if you want the compiler to 251 search directory <samp><var>dirname</var><span class="file">/include</span></samp> for locally installed 252 header files <em>instead</em> of <samp><span class="file">/usr/local/include</span></samp>. 253 254 <p>You should specify <samp><span class="option">--with-local-prefix</span></samp> <strong>only</strong> if your 255 site has a different convention (not <samp><span class="file">/usr/local</span></samp>) for where to put 256 site-specific files. 257 258 <p>The default value for <samp><span class="option">--with-local-prefix</span></samp> is <samp><span class="file">/usr/local</span></samp> 259 regardless of the value of <samp><span class="option">--prefix</span></samp>. Specifying 260 <samp><span class="option">--prefix</span></samp> has no effect on which directory GCC searches for 261 local header files. This may seem counterintuitive, but actually it is 262 logical. 263 264 <p>The purpose of <samp><span class="option">--prefix</span></samp> is to specify where to <em>install 265 GCC</em>. The local header files in <samp><span class="file">/usr/local/include</span></samp>—if you put 266 any in that directory—are not part of GCC. They are part of other 267 programs—perhaps many others. (GCC installs its own header files in 268 another directory which is based on the <samp><span class="option">--prefix</span></samp> value.) 269 270 <p>Both the local-prefix include directory and the GCC-prefix include 271 directory are part of GCC's “system include” directories. Although these 272 two directories are not fixed, they need to be searched in the proper 273 order for the correct processing of the include_next directive. The 274 local-prefix include directory is searched before the GCC-prefix 275 include directory. Another characteristic of system include directories 276 is that pedantic warnings are turned off for headers in these directories. 277 278 <p>Some autoconf macros add <samp><span class="option">-I </span><var>directory</var></samp> options to the 279 compiler command line, to ensure that directories containing installed 280 packages' headers are searched. When <var>directory</var> is one of GCC's 281 system include directories, GCC will ignore the option so that system 282 directories continue to be processed in the correct order. This 283 may result in a search order different from what was specified but the 284 directory will still be searched. 285 286 <p>GCC automatically searches for ordinary libraries using 287 <samp><span class="env">GCC_EXEC_PREFIX</span></samp>. Thus, when the same installation prefix is 288 used for both GCC and packages, GCC will automatically search for 289 both headers and libraries. This provides a configuration that is 290 easy to use. GCC behaves in a manner similar to that when it is 291 installed as a system compiler in <samp><span class="file">/usr</span></samp>. 292 293 <p>Sites that need to install multiple versions of GCC may not want to 294 use the above simple configuration. It is possible to use the 295 <samp><span class="option">--program-prefix</span></samp>, <samp><span class="option">--program-suffix</span></samp> and 296 <samp><span class="option">--program-transform-name</span></samp> options to install multiple versions 297 into a single directory, but it may be simpler to use different prefixes 298 and the <samp><span class="option">--with-local-prefix</span></samp> option to specify the location of the 299 site-specific files for each version. It will then be necessary for 300 users to specify explicitly the location of local site libraries 301 (e.g., with <samp><span class="env">LIBRARY_PATH</span></samp>). 302 303 <p>The same value can be used for both <samp><span class="option">--with-local-prefix</span></samp> and 304 <samp><span class="option">--prefix</span></samp> provided it is not <samp><span class="file">/usr</span></samp>. This can be used 305 to avoid the default search of <samp><span class="file">/usr/local/include</span></samp>. 306 307 <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 The directory you use for <samp><span class="option">--with-local-prefix</span></samp> <strong>must not</strong> 309 contain any of the system's standard header files. If it did contain 310 them, certain programs would be miscompiled (including GNU Emacs, on 311 certain targets), because this would override and nullify the header 312 file corrections made by the <samp><span class="command">fixincludes</span></samp> script. 313 314 <p>Indications are that people who use this option use it based on mistaken 315 ideas of what it is for. People use it as if it specified where to 316 install part of GCC. Perhaps they make this assumption because 317 installing GCC creates the directory. 318 319 <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 header files, rather than <samp><span class="file">/usr/include</span></samp>. This option is most useful 321 if you are creating a compiler that should be isolated from the system 322 as much as possible. It is most commonly used with the 323 <samp><span class="option">--with-sysroot</span></samp> option and will cause GCC to search 324 <var>dirname</var> inside the system root specified by that option. 325 326 <br><dt><code>--enable-shared[=</code><var>package</var><code>[,...]]</code><dd>Build shared versions of libraries, if shared libraries are supported on 327 the target platform. Unlike GCC 2.95.x and earlier, shared libraries 328 are enabled by default on all platforms that support shared libraries. 329 330 <p>If a list of packages is given as an argument, build shared libraries 331 only for the listed packages. For other packages, only static libraries 332 will be built. Package names currently recognized in the GCC tree are 333 ‘<samp><span class="samp">libgcc</span></samp>’ (also known as ‘<samp><span class="samp">gcc</span></samp>’), ‘<samp><span class="samp">libstdc++</span></samp>’ (not 334 ‘<samp><span class="samp">libstdc++-v3</span></samp>’), ‘<samp><span class="samp">libffi</span></samp>’, ‘<samp><span class="samp">zlib</span></samp>’, ‘<samp><span class="samp">boehm-gc</span></samp>’, 335 ‘<samp><span class="samp">ada</span></samp>’, ‘<samp><span class="samp">libada</span></samp>’, ‘<samp><span class="samp">libjava</span></samp>’, ‘<samp><span class="samp">libgo</span></samp>’, and ‘<samp><span class="samp">libobjc</span></samp>’. 336 Note ‘<samp><span class="samp">libiberty</span></samp>’ does not support shared libraries at all. 337 338 <p>Use <samp><span class="option">--disable-shared</span></samp> to build only static libraries. Note that 339 <samp><span class="option">--disable-shared</span></samp> does not accept a list of package names as 340 argument, only <samp><span class="option">--enable-shared</span></samp> does. 341 342 <p>Contrast with <samp><span class="option">--enable-host-shared</span></samp>, which affects <em>host</em> 343 code. 344 345 <br><dt><code>--enable-host-shared</code><dd>Specify that the <em>host</em> code should be built into position-independent 346 machine code (with -fPIC), allowing it to be used within shared libraries, 347 but yielding a slightly slower compiler. 348 349 <p>This option is required when building the libgccjit.so library. 350 351 <p>Contrast with <samp><span class="option">--enable-shared</span></samp>, which affects <em>target</em> 352 libraries. 353 354 <br><dt><code><a name="with_002dgnu_002das"></a>--with-gnu-as</code><dd>Specify that the compiler should assume that the 355 assembler it finds is the GNU assembler. However, this does not modify 356 the rules to find an assembler and will result in confusion if the 357 assembler found is not actually the GNU assembler. (Confusion may also 358 result if the compiler finds the GNU assembler but has not been 359 configured with <samp><span class="option">--with-gnu-as</span></samp>.) If you have more than one 360 assembler installed on your system, you may want to use this option in 361 connection with <samp><span class="option">--with-as=</span><var>pathname</var></samp> or 362 <samp><span class="option">--with-build-time-tools=</span><var>pathname</var></samp>. 363 364 <p>The following systems are the only ones where it makes a difference 365 whether you use the GNU assembler. On any other system, 366 <samp><span class="option">--with-gnu-as</span></samp> has no effect. 367 368 <ul> 369 <li>‘<samp><span class="samp">hppa1.0-</span><var>any</var><span class="samp">-</span><var>any</var></samp>’ 370 <li>‘<samp><span class="samp">hppa1.1-</span><var>any</var><span class="samp">-</span><var>any</var></samp>’ 371 <li>‘<samp><span class="samp">sparc-sun-solaris2.</span><var>any</var></samp>’ 372 <li>‘<samp><span class="samp">sparc64-</span><var>any</var><span class="samp">-solaris2.</span><var>any</var></samp>’ 373 </ul> 374 375 <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 <var>pathname</var>, rather than the one found by the standard rules to find 377 an assembler, which are: 378 <ul> 379 <li>Unless GCC is being built with a cross compiler, check the 380 <samp><var>libexec</var><span class="file">/gcc/</span><var>target</var><span class="file">/</span><var>version</var></samp> directory. 381 <var>libexec</var> defaults to <samp><var>exec-prefix</var><span class="file">/libexec</span></samp>; 382 <var>exec-prefix</var> defaults to <var>prefix</var>, which 383 defaults to <samp><span class="file">/usr/local</span></samp> unless overridden by the 384 <samp><span class="option">--prefix=</span><var>pathname</var></samp> switch described above. <var>target</var> 385 is the target system triple, such as ‘<samp><span class="samp">sparc-sun-solaris2.7</span></samp>’, and 386 <var>version</var> denotes the GCC version, such as 3.0. 387 388 <li>If the target system is the same that you are building on, check 389 operating system specific directories (e.g. <samp><span class="file">/usr/ccs/bin</span></samp> on 390 Sun Solaris 2). 391 392 <li>Check in the <samp><span class="env">PATH</span></samp> for a tool whose name is prefixed by the 393 target system triple. 394 395 <li>Check in the <samp><span class="env">PATH</span></samp> for a tool whose name is not prefixed by the 396 target system triple, if the host and target system triple are 397 the same (in other words, we use a host tool if it can be used for 398 the target as well). 399 </ul> 400 401 <p>You may want to use <samp><span class="option">--with-as</span></samp> if no assembler 402 is installed in the directories listed above, or if you have multiple 403 assemblers installed and want to choose one that is not found by the 404 above rules. 405 406 <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 but for the linker. 408 409 <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 but for the linker. 411 412 <br><dt><code>--with-stabs</code><dd>Specify that stabs debugging 413 information should be used instead of whatever format the host normally 414 uses. Normally GCC uses the same debug format as the host system. 415 416 <p>On MIPS based systems and on Alphas, you must specify whether you want 417 GCC to create the normal ECOFF debugging format, or to use BSD-style 418 stabs passed through the ECOFF symbol table. The normal ECOFF debug 419 format cannot fully handle languages other than C. BSD stabs format can 420 handle other languages, but it only works with the GNU debugger GDB. 421 422 <p>Normally, GCC uses the ECOFF debugging format by default; if you 423 prefer BSD stabs, specify <samp><span class="option">--with-stabs</span></samp> when you configure GCC. 424 425 <p>No matter which default you choose when you configure GCC, the user 426 can use the <samp><span class="option">-gcoff</span></samp> and <samp><span class="option">-gstabs+</span></samp> options to specify explicitly 427 the debug format for a particular compilation. 428 429 <p><samp><span class="option">--with-stabs</span></samp> is meaningful on the ISC system on the 386, also, if 430 <samp><span class="option">--with-gas</span></samp> is used. It selects use of stabs debugging 431 information embedded in COFF output. This kind of debugging information 432 supports C++ well; ordinary COFF debugging information does not. 433 434 <p><samp><span class="option">--with-stabs</span></samp> is also meaningful on 386 systems running SVR4. It 435 selects use of stabs debugging information embedded in ELF output. The 436 C++ compiler currently (2.6.0) does not support the DWARF debugging 437 information normally used on 386 SVR4 platforms; stabs provide a 438 workable alternative. This requires gas and gdb, as the normal SVR4 439 tools can not generate or interpret stabs. 440 441 <br><dt><code>--with-tls=</code><var>dialect</var><dd>Specify the default TLS dialect, for systems were there is a choice. 442 For ARM targets, possible values for <var>dialect</var> are <code>gnu</code> or 443 <code>gnu2</code>, which select between the original GNU dialect and the GNU TLS 444 descriptor-based dialect. 445 446 <br><dt><code>--enable-multiarch</code><dd>Specify whether to enable or disable multiarch support. The default is 447 to check for glibc start files in a multiarch location, and enable it 448 if the files are found. The auto detection is enabled for native builds, 449 and for cross builds configured with <samp><span class="option">--with-sysroot</span></samp>, and without 450 <samp><span class="option">--with-native-system-header-dir</span></samp>. 451 More documentation about multiarch can be found at 452 <a href="http://wiki.debian.org/Multiarch">http://wiki.debian.org/Multiarch</a>. 453 454 <br><dt><code>--enable-vtable-verify</code><dd>Specify whether to enable or disable the vtable verification feature. 455 Enabling this feature causes libstdc++ to be built with its virtual calls 456 in verifiable mode. This means that, when linked with libvtv, every 457 virtual call in libstdc++ will verify the vtable pointer through which the 458 call will be made before actually making the call. If not linked with libvtv, 459 the verifier will call stub functions (in libstdc++ itself) and do nothing. 460 If vtable verification is disabled, then libstdc++ is not built with its 461 virtual calls in verifiable mode at all. However the libvtv library will 462 still be built (see <samp><span class="option">--disable-libvtv</span></samp> to turn off building libvtv). 463 <samp><span class="option">--disable-vtable-verify</span></samp> is the default. 464 465 <br><dt><code>--disable-multilib</code><dd>Specify that multiple target 466 libraries to support different target variants, calling 467 conventions, etc. should not be built. The default is to build a 468 predefined set of them. 469 470 <p>Some targets provide finer-grained control over which multilibs are built 471 (e.g., <samp><span class="option">--disable-softfloat</span></samp>): 472 <dl> 473 <dt><code>arm-*-*</code><dd>fpu, 26bit, underscore, interwork, biendian, nofmult. 474 475 <br><dt><code>m68*-*-*</code><dd>softfloat, m68881, m68000, m68020. 476 477 <br><dt><code>mips*-*-*</code><dd>single-float, biendian, softfloat. 478 479 <br><dt><code>powerpc*-*-*, rs6000*-*-*</code><dd>aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian, 480 sysv, aix. 481 482 </dl> 483 484 <br><dt><code>--with-multilib-list=</code><var>list</var><dt><code>--without-multilib-list</code><dd>Specify what multilibs to build. 485 Currently only implemented for sh*-*-* and x86-64-*-linux*. 486 487 <dl> 488 <dt><code>sh*-*-*</code><dd><var>list</var> is a comma separated list of CPU names. These must be of the 489 form <code>sh*</code> or <code>m*</code> (in which case they match the compiler option 490 for that processor). The list should not contain any endian options - 491 these are handled by <samp><span class="option">--with-endian</span></samp>. 492 493 <p>If <var>list</var> is empty, then there will be no multilibs for extra 494 processors. The multilib for the secondary endian remains enabled. 495 496 <p>As a special case, if an entry in the list starts with a <code>!</code> 497 (exclamation point), then it is added to the list of excluded multilibs. 498 Entries of this sort should be compatible with ‘<samp><span class="samp">MULTILIB_EXCLUDES</span></samp>’ 499 (once the leading <code>!</code> has been stripped). 500 501 <p>If <samp><span class="option">--with-multilib-list</span></samp> is not given, then a default set of 502 multilibs is selected based on the value of <samp><span class="option">--target</span></samp>. This is 503 usually the complete set of libraries, but some targets imply a more 504 specialized subset. 505 506 <p>Example 1: to configure a compiler for SH4A only, but supporting both 507 endians, with little endian being the default: 508 <pre class="smallexample"> --with-cpu=sh4a --with-endian=little,big --with-multilib-list= 509 </pre> 510 <p>Example 2: to configure a compiler for both SH4A and SH4AL-DSP, but with 511 only little endian SH4AL: 512 <pre class="smallexample"> --with-cpu=sh4a --with-endian=little,big \ 513 --with-multilib-list=sh4al,!mb/m4al 514 </pre> 515 <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 <code>mx32</code> to enable 32-bit, 64-bit and x32 run-time libraries, 517 respectively. If <var>list</var> is empty, then there will be no multilibs 518 and only the default run-time library will be enabled. 519 520 <p>If <samp><span class="option">--with-multilib-list</span></samp> is not given, then only 32-bit and 521 64-bit run-time libraries will be enabled. 522 </dl> 523 524 <br><dt><code>--with-endian=</code><var>endians</var><dd>Specify what endians to use. 525 Currently only implemented for sh*-*-*. 526 527 <p><var>endians</var> may be one of the following: 528 <dl> 529 <dt><code>big</code><dd>Use big endian exclusively. 530 <br><dt><code>little</code><dd>Use little endian exclusively. 531 <br><dt><code>big,little</code><dd>Use big endian by default. Provide a multilib for little endian. 532 <br><dt><code>little,big</code><dd>Use little endian by default. Provide a multilib for big endian. 533 </dl> 534 535 <br><dt><code>--enable-threads</code><dd>Specify that the target 536 supports threads. This affects the Objective-C compiler and runtime 537 library, and exception handling for other languages like C++ and Java. 538 On some systems, this is the default. 539 540 <p>In general, the best (and, in many cases, the only known) threading 541 model available will be configured for use. Beware that on some 542 systems, GCC has not been taught what threading models are generally 543 available for the system. In this case, <samp><span class="option">--enable-threads</span></samp> is an 544 alias for <samp><span class="option">--enable-threads=single</span></samp>. 545 546 <br><dt><code>--disable-threads</code><dd>Specify that threading support should be disabled for the system. 547 This is an alias for <samp><span class="option">--enable-threads=single</span></samp>. 548 549 <br><dt><code>--enable-threads=</code><var>lib</var><dd>Specify that 550 <var>lib</var> is the thread support library. This affects the Objective-C 551 compiler and runtime library, and exception handling for other languages 552 like C++ and Java. The possibilities for <var>lib</var> are: 553 554 <dl> 555 <dt><code>aix</code><dd>AIX thread support. 556 <br><dt><code>dce</code><dd>DCE thread support. 557 <br><dt><code>lynx</code><dd>LynxOS thread support. 558 <br><dt><code>mipssde</code><dd>MIPS SDE thread support. 559 <br><dt><code>no</code><dd>This is an alias for ‘<samp><span class="samp">single</span></samp>’. 560 <br><dt><code>posix</code><dd>Generic POSIX/Unix98 thread support. 561 <br><dt><code>rtems</code><dd>RTEMS thread support. 562 <br><dt><code>single</code><dd>Disable thread support, should work for all platforms. 563 <br><dt><code>tpf</code><dd>TPF thread support. 564 <br><dt><code>vxworks</code><dd>VxWorks thread support. 565 <br><dt><code>win32</code><dd>Microsoft Win32 API thread support. 566 </dl> 567 568 <br><dt><code>--enable-tls</code><dd>Specify that the target supports TLS (Thread Local Storage). Usually 569 configure can correctly determine if TLS is supported. In cases where 570 it guesses incorrectly, TLS can be explicitly enabled or disabled with 571 <samp><span class="option">--enable-tls</span></samp> or <samp><span class="option">--disable-tls</span></samp>. This can happen if 572 the assembler supports TLS but the C library does not, or if the 573 assumptions made by the configure test are incorrect. 574 575 <br><dt><code>--disable-tls</code><dd>Specify that the target does not support TLS. 576 This is an alias for <samp><span class="option">--enable-tls=no</span></samp>. 577 578 <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 <var>cpu</var> will be used as the default value of the <samp><span class="option">-mcpu=</span></samp> switch. 580 This option is only supported on some targets, including ARC, ARM, i386, M68k, 581 PowerPC, and SPARC. It is mandatory for ARC. The <samp><span class="option">--with-cpu-32</span></samp> and 582 <samp><span class="option">--with-cpu-64</span></samp> options specify separate default CPUs for 583 32-bit and 64-bit modes; these options are only supported for i386, 584 x86-64 and PowerPC. 585 586 <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 <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 options and for <samp><span class="option">-mhard-float</span></samp> or <samp><span class="option">-msoft-float</span></samp>. As with 589 <samp><span class="option">--with-cpu</span></samp>, which switches will be accepted and acceptable values 590 of the arguments depend on the target. 591 592 <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 This option is only supported on ARM targets. 594 595 <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 and will thus generally also control the setting of this option for 597 libraries. This option is only supported on Epiphany targets. 598 599 <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 ISA for floating-point arithmetics. You can select either ‘<samp><span class="samp">sse</span></samp>’ which 601 enables <samp><span class="option">-msse2</span></samp> or ‘<samp><span class="samp">avx</span></samp>’ which enables <samp><span class="option">-mavx</span></samp> by default. 602 This option is only supported on i386 and x86-64 targets. 603 604 <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 the o32 ABI. The possibilities for <var>mode</var> are: 606 <dl> 607 <dt><code>32</code><dd>Use the o32 FP32 ABI extension, as with the <samp><span class="option">-mfp32</span></samp> command-line 608 option. 609 <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 option. 611 <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 option. 613 </dl> 614 In the absence of this configuration option the default is to use the o32 615 FP32 ABI extension. 616 617 <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 the o32 ABI. 619 620 <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 the o32 ABI. This is normally used in conjunction with 622 <samp><span class="option">--with-fp-32=64</span></samp> in order to target the o32 FP64A ABI extension. 623 624 <br><dt><code>--with-nan=</code><var>encoding</var><dd>On MIPS targets, set the default encoding convention to use for the 625 special not-a-number (NaN) IEEE 754 floating-point data. The 626 possibilities for <var>encoding</var> are: 627 <dl> 628 <dt><code>legacy</code><dd>Use the legacy encoding, as with the <samp><span class="option">-mnan=legacy</span></samp> command-line 629 option. 630 <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 option. 632 </dl> 633 To use this configuration option you must have an assembler version 634 installed that supports the <samp><span class="option">-mnan=</span></samp> command-line option too. 635 In the absence of this configuration option the default convention is 636 the legacy encoding, as when neither of the <samp><span class="option">-mnan=2008</span></samp> and 637 <samp><span class="option">-mnan=legacy</span></samp> command-line options has been used. 638 639 <br><dt><code>--with-divide=</code><var>type</var><dd>Specify how the compiler should generate code for checking for 640 division by zero. This option is only supported on the MIPS target. 641 The possibilities for <var>type</var> are: 642 <dl> 643 <dt><code>traps</code><dd>Division by zero checks use conditional traps (this is the default on 644 systems that support conditional traps). 645 <br><dt><code>breaks</code><dd>Division by zero checks use the break instruction. 646 </dl> 647 648 <!-- If you make -with-llsc the default for additional targets, --> 649 <!-- update the -with-llsc description in the MIPS section below. --> 650 <br><dt><code>--with-llsc</code><dd>On MIPS targets, make <samp><span class="option">-mllsc</span></samp> the default when no 651 <samp><span class="option">-mno-llsc</span></samp> option is passed. This is the default for 652 Linux-based targets, as the kernel will emulate them if the ISA does 653 not provide them. 654 655 <br><dt><code>--without-llsc</code><dd>On MIPS targets, make <samp><span class="option">-mno-llsc</span></samp> the default when no 656 <samp><span class="option">-mllsc</span></samp> option is passed. 657 658 <br><dt><code>--with-synci</code><dd>On MIPS targets, make <samp><span class="option">-msynci</span></samp> the default when no 659 <samp><span class="option">-mno-synci</span></samp> option is passed. 660 661 <br><dt><code>--without-synci</code><dd>On MIPS targets, make <samp><span class="option">-mno-synci</span></samp> the default when no 662 <samp><span class="option">-msynci</span></samp> option is passed. This is the default. 663 664 <br><dt><code>--with-mips-plt</code><dd>On MIPS targets, make use of copy relocations and PLTs. 665 These features are extensions to the traditional 666 SVR4-based MIPS ABIs and require support from GNU binutils 667 and the runtime C library. 668 669 <br><dt><code>--enable-__cxa_atexit</code><dd>Define if you want to use __cxa_atexit, rather than atexit, to 670 register C++ destructors for local statics and global objects. 671 This is essential for fully standards-compliant handling of 672 destructors, but requires __cxa_atexit in libc. This option is currently 673 only available on systems with GNU libc. When enabled, this will cause 674 <samp><span class="option">-fuse-cxa-atexit</span></samp> to be passed by default. 675 676 <br><dt><code>--enable-gnu-indirect-function</code><dd>Define if you want to enable the <code>ifunc</code> attribute. This option is 677 currently only available on systems with GNU libc on certain targets. 678 679 <br><dt><code>--enable-target-optspace</code><dd>Specify that target 680 libraries should be optimized for code space instead of code speed. 681 This is the default for the m32r platform. 682 683 <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 in <samp><var>prefix</var><span class="file">/</span><var>dirname</var><span class="file">/cpp</span></samp>, in addition to <var>bindir</var>. 685 686 <br><dt><code>--enable-comdat</code><dd>Enable COMDAT group support. This is primarily used to override the 687 automatically detected value. 688 689 <br><dt><code>--enable-initfini-array</code><dd>Force the use of sections <code>.init_array</code> and <code>.fini_array</code> 690 (instead of <code>.init</code> and <code>.fini</code>) for constructors and 691 destructors. Option <samp><span class="option">--disable-initfini-array</span></samp> has the 692 opposite effect. If neither option is specified, the configure script 693 will try to guess whether the <code>.init_array</code> and 694 <code>.fini_array</code> sections are supported and, if they are, use them. 695 696 <br><dt><code>--enable-link-mutex</code><dd>When building GCC, use a mutex to avoid linking the compilers for 697 multiple languages at the same time, to avoid thrashing on build 698 systems with limited free memory. The default is not to use such a mutex. 699 700 <br><dt><code>--enable-maintainer-mode</code><dd>The build rules that regenerate the Autoconf and Automake output files as 701 well as the GCC master message catalog <samp><span class="file">gcc.pot</span></samp> are normally 702 disabled. This is because it can only be rebuilt if the complete source 703 tree is present. If you have changed the sources and want to rebuild the 704 catalog, configuring with <samp><span class="option">--enable-maintainer-mode</span></samp> will enable 705 this. Note that you need a recent version of the <code>gettext</code> tools 706 to do so. 707 708 <br><dt><code>--disable-bootstrap</code><dd>For a native build, the default configuration is to perform 709 a 3-stage bootstrap of the compiler when ‘<samp><span class="samp">make</span></samp>’ is invoked, 710 testing that GCC can compile itself correctly. If you want to disable 711 this process, you can configure with <samp><span class="option">--disable-bootstrap</span></samp>. 712 713 <br><dt><code>--enable-bootstrap</code><dd>In special cases, you may want to perform a 3-stage build 714 even if the target and host triplets are different. 715 This is possible when the host can run code compiled for 716 the target (e.g. host is i686-linux, target is i486-linux). 717 Starting from GCC 4.2, to do this you have to configure explicitly 718 with <samp><span class="option">--enable-bootstrap</span></samp>. 719 720 <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 info manuals and man pages that are built from the .texi files are present 722 in the SVN development tree. When building GCC from that development tree, 723 or from one of our snapshots, those generated files are placed in your 724 build directory, which allows for the source to be in a readonly 725 directory. 726 727 <p>If you configure with <samp><span class="option">--enable-generated-files-in-srcdir</span></samp> then those 728 generated files will go into the source directory. This is mainly intended 729 for generating release or prerelease tarballs of the GCC sources, since it 730 is not a requirement that the users of source releases to have flex, Bison, 731 or makeinfo. 732 733 <br><dt><code>--enable-version-specific-runtime-libs</code><dd>Specify 734 that runtime libraries should be installed in the compiler specific 735 subdirectory (<samp><var>libdir</var><span class="file">/gcc</span></samp>) rather than the usual places. In 736 addition, ‘<samp><span class="samp">libstdc++</span></samp>’'s include files will be installed into 737 <samp><var>libdir</var></samp> unless you overruled it by using 738 <samp><span class="option">--with-gxx-include-dir=</span><var>dirname</var></samp>. Using this option is 739 particularly useful if you intend to use several versions of GCC in 740 parallel. This is currently supported by ‘<samp><span class="samp">libgfortran</span></samp>’, 741 ‘<samp><span class="samp">libjava</span></samp>’, ‘<samp><span class="samp">libstdc++</span></samp>’, and ‘<samp><span class="samp">libobjc</span></samp>’. 742 743 <br><dt><code><a name="WithAixSoname"></a>--with-aix-soname=‘</code><samp><span class="samp">aix</span></samp><code>’, ‘</code><samp><span class="samp">svr4</span></samp><code>’ or ‘</code><samp><span class="samp">both</span></samp><code>’</code><dd>Traditional AIX shared library versioning (versioned <code>Shared Object</code> 744 files as members of unversioned <code>Archive Library</code> files named 745 ‘<samp><span class="samp">lib.a</span></samp>’) causes numerous headaches for package managers. However, 746 <code>Import Files</code> as members of <code>Archive Library</code> files allow for 747 <strong>filename-based versioning</strong> of shared libraries as seen on Linux/SVR4, 748 where this is called the "SONAME". But as they prevent static linking, 749 <code>Import Files</code> may be used with <code>Runtime Linking</code> only, where the 750 linker does search for ‘<samp><span class="samp">libNAME.so</span></samp>’ before ‘<samp><span class="samp">libNAME.a</span></samp>’ library 751 filenames with the ‘<samp><span class="samp">-lNAME</span></samp>’ linker flag. 752 753 <p><a name="AixLdCommand"></a>For detailed information please refer to the AIX 754 <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. 755 756 <p>As long as shared library creation is enabled, upon: 757 <dl> 758 <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 <ul> 760 <li>using the ‘<samp><span class="samp">libNAME.a</span></samp>’ filename scheme 761 <li>with the <code>Shared Object</code> file as archive member named 762 ‘<samp><span class="samp">libNAME.so.V</span></samp>’ (except for ‘<samp><span class="samp">libgcc_s</span></samp>’, where the <code>Shared 763 Object</code> file is named ‘<samp><span class="samp">shr.o</span></samp>’ for backwards compatibility), which 764 <ul> 765 <li>is used for runtime loading from inside the ‘<samp><span class="samp">libNAME.a</span></samp>’ file 766 <li>is used for dynamic loading via 767 <code>dlopen("libNAME.a(libNAME.so.V)", RTLD_MEMBER)</code> 768 <li>is used for shared linking 769 <li>is used for static linking, so no separate <code>Static Archive 770 Library</code> file is needed 771 </ul> 772 </ul> 773 <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 <ul> 775 <li>using the ‘<samp><span class="samp">libNAME.so.V</span></samp>’ filename scheme 776 <li>with the <code>Shared Object</code> file as archive member named 777 ‘<samp><span class="samp">shr.o</span></samp>’, which 778 <ul> 779 <li>is created with the <code>-G linker flag</code> 780 <li>has the <code>F_LOADONLY</code> flag set 781 <li>is used for runtime loading from inside the ‘<samp><span class="samp">libNAME.so.V</span></samp>’ file 782 <li>is used for dynamic loading via <code>dlopen("libNAME.so.V(shr.o)", 783 RTLD_MEMBER)</code> 784 </ul> 785 <li>with the <code>Import File</code> as archive member named ‘<samp><span class="samp">shr.imp</span></samp>’, 786 which 787 <ul> 788 <li>refers to ‘<samp><span class="samp">libNAME.so.V(shr.o)</span></samp>’ as the "SONAME", to be recorded 789 in the <code>Loader Section</code> of subsequent binaries 790 <li>indicates whether ‘<samp><span class="samp">libNAME.so.V(shr.o)</span></samp>’ is 32 or 64 bit 791 <li>lists all the public symbols exported by ‘<samp><span class="samp">lib.so.V(shr.o)</span></samp>’, 792 eventually decorated with the <code>‘</code><samp><span class="samp">weak</span></samp><code>’ Keyword</code> 793 <li>is necessary for shared linking against ‘<samp><span class="samp">lib.so.V(shr.o)</span></samp>’ 794 </ul> 795 </ul> 796 A symbolic link using the ‘<samp><span class="samp">libNAME.so</span></samp>’ filename scheme is created: 797 <ul> 798 <li>pointing to the ‘<samp><span class="samp">libNAME.so.V</span></samp>’ <code>Shared Archive Library</code> file 799 <li>to permit the <code>ld Command</code> to find ‘<samp><span class="samp">lib.so.V(shr.imp)</span></samp>’ via 800 the ‘<samp><span class="samp">-lNAME</span></samp>’ argument (requires <code>Runtime Linking</code> to be enabled) 801 <li>to permit dynamic loading of ‘<samp><span class="samp">lib.so.V(shr.o)</span></samp>’ without the need 802 to specify the version number via <code>dlopen("libNAME.so(shr.o)", 803 RTLD_MEMBER)</code> 804 </ul> 805 </dl> 806 807 <p>As long as static library creation is enabled, upon: 808 <dl> 809 <dt><code>--with-aix-soname=svr4</code><dd> A <code>Static Archive Library</code> is created: 810 <ul> 811 <li>using the ‘<samp><span class="samp">libNAME.a</span></samp>’ filename scheme 812 <li>with all the <code>Static Object</code> files as archive members, which 813 <ul> 814 <li>are used for static linking 815 </ul> 816 </ul> 817 </dl> 818 819 <p>While the aix-soname=‘<samp><span class="samp">svr4</span></samp>’ option does not create <code>Shared Object</code> 820 files as members of unversioned <code>Archive Library</code> files any more, package 821 managers still are responsible to 822 <a href="./specific.html#TransferAixShobj">transfer</a> <code>Shared Object</code> files 823 found as member of a previously installed unversioned <code>Archive Library</code> 824 file into the newly installed <code>Archive Library</code> file with the same 825 filename. 826 827 <p><em>WARNING:</em> Creating <code>Shared Object</code> files with <code>Runtime Linking</code> 828 enabled may bloat the TOC, eventually leading to <code>TOC overflow</code> errors, 829 requiring the use of either the <samp><span class="option">-Wl,-bbigtoc</span></samp> linker flag (seen to 830 break with the <code>GDB</code> debugger) or some of the TOC-related compiler flags, 831 see “RS/6000 and PowerPC Options” in the main manual. 832 833 <p><samp><span class="option">--with-aix-soname</span></samp> is currently supported by ‘<samp><span class="samp">libgcc_s</span></samp>’ only, so 834 this option is still experimental and not for normal use yet. 835 836 <p>Default is the traditional behaviour <samp><span class="option">--with-aix-soname=‘</span><samp><span class="samp">aix</span></samp><span class="option">’</span></samp>. 837 838 <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 their runtime libraries should be built. For a list of valid values for 840 <var>langN</var> you can issue the following command in the 841 <samp><span class="file">gcc</span></samp> directory of your GCC source tree:<br> 842 <pre class="smallexample"> grep language= */config-lang.in 843 </pre> 844 <p>Currently, you can use any of the following: 845 <code>all</code>, <code>ada</code>, <code>c</code>, <code>c++</code>, <code>fortran</code>, 846 <code>go</code>, <code>java</code>, <code>objc</code>, <code>obj-c++</code>. 847 Building the Ada compiler has special requirements, see below. 848 If you do not pass this flag, or specify the option <code>all</code>, then all 849 default languages available in the <samp><span class="file">gcc</span></samp> sub-tree will be configured. 850 Ada, Go and Objective-C++ are not default languages; the rest are. 851 852 <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 libraries should be built with the system C compiler during stage 1 of 854 the bootstrap process, rather than only in later stages with the 855 bootstrapped C compiler. The list of valid values is the same as for 856 <samp><span class="option">--enable-languages</span></samp>, and the option <code>all</code> will select all 857 of the languages enabled by <samp><span class="option">--enable-languages</span></samp>. This option is 858 primarily useful for GCC development; for instance, when a development 859 version of the compiler cannot bootstrap due to compiler bugs, or when 860 one is debugging front ends other than the C front end. When this 861 option is used, one can then build the target libraries for the 862 specified languages with the stage-1 compiler by using <samp><span class="command">make 863 stage1-bubble all-target</span></samp>, or run the testsuite on the stage-1 compiler 864 for the specified languages using <samp><span class="command">make stage1-start check-gcc</span></samp>. 865 866 <br><dt><code>--disable-libada</code><dd>Specify that the run-time libraries and tools used by GNAT should not 867 be built. This can be useful for debugging, or for compatibility with 868 previous Ada build procedures, when it was required to explicitly 869 do a ‘<samp><span class="samp">make -C gcc gnatlib_and_tools</span></samp>’. 870 871 <br><dt><code>--disable-libsanitizer</code><dd>Specify that the run-time libraries for the various sanitizers should 872 not be built. 873 874 <br><dt><code>--disable-libssp</code><dd>Specify that the run-time libraries for stack smashing protection 875 should not be built. 876 877 <br><dt><code>--disable-libquadmath</code><dd>Specify that the GCC quad-precision math library should not be built. 878 On some systems, the library is required to be linkable when building 879 the Fortran front end, unless <samp><span class="option">--disable-libquadmath-support</span></samp> 880 is used. 881 882 <br><dt><code>--disable-libquadmath-support</code><dd>Specify that the Fortran front end and <code>libgfortran</code> do not add 883 support for <code>libquadmath</code> on systems supporting it. 884 885 <br><dt><code>--disable-libgomp</code><dd>Specify that the GNU Offloading and Multi Processing Runtime Library 886 should not be built. 887 888 <br><dt><code>--disable-libvtv</code><dd>Specify that the run-time libraries used by vtable verification 889 should not be built. 890 891 <br><dt><code>--with-dwarf2</code><dd>Specify that the compiler should 892 use DWARF 2 debugging information as the default. 893 894 <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 These are compilers that are able to generate either 64-bit or 32-bit 896 code. Typically, the corresponding 32-bit target, e.g. 897 powerpc-linux for powerpc64-linux, only generates 32-bit code. This 898 option enables the 32-bit target to be a bi-arch compiler, which is 899 useful when you want a bi-arch compiler that defaults to 32-bit, and 900 you are building a bi-arch or multi-arch binutils in a combined tree. 901 On mips-linux, this will build a tri-arch compiler (ABI o32/n32/64), 902 defaulted to o32. 903 Currently, this option only affects sparc-linux, powerpc-linux, x86-linux, 904 mips-linux and s390-linux. 905 906 <br><dt><code>--enable-secureplt</code><dd>This option enables <samp><span class="option">-msecure-plt</span></samp> by default for powerpc-linux. 907 See “RS/6000 and PowerPC Options” in the main manual 908 909 <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 See “i386 and x86-64 Options” in the main manual 911 912 <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 to look up installations paths in the registry using the following key: 914 915 <pre class="smallexample"> <code>HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\</code><var>key</var> 916 </pre> 917 <p><var>key</var> defaults to GCC version number, and can be overridden by the 918 <samp><span class="option">--enable-win32-registry=</span><var>key</var></samp> option. Vendors and distributors 919 who use custom installers are encouraged to provide a different key, 920 perhaps one comprised of vendor name and GCC version number, to 921 avoid conflict with existing installations. This feature is enabled 922 by default, and can be disabled by <samp><span class="option">--disable-win32-registry</span></samp> 923 option. This option has no effect on the other hosts. 924 925 <br><dt><code>--nfp</code><dd>Specify that the machine does not have a floating point unit. This 926 option only applies to ‘<samp><span class="samp">m68k-sun-sunos</span><var>n</var></samp>’. On any other 927 system, <samp><span class="option">--nfp</span></samp> has no effect. 928 929 <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 compiler are built with <samp><span class="option">-Werror</span></samp> in bootstrap stage2 and later. 931 If you don't specify it, <samp><span class="option">-Werror</span></samp> is turned on for the main 932 development trunk. However it defaults to off for release branches and 933 final releases. The specific files which get <samp><span class="option">-Werror</span></samp> are 934 controlled by the Makefiles. 935 936 <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 consistency checks of the requested complexity. This does not change the 938 generated code, but adds error checking within the compiler. This will 939 slow down the compiler and may only work properly if you are building 940 the compiler with GCC. This is ‘<samp><span class="samp">yes</span></samp>’ by default when building 941 from SVN or snapshots, but ‘<samp><span class="samp">release</span></samp>’ for releases. The default 942 for building the stage1 compiler is ‘<samp><span class="samp">yes</span></samp>’. More control 943 over the checks may be had by specifying <var>list</var>. The categories of 944 checks available are ‘<samp><span class="samp">yes</span></samp>’ (most common checks 945 ‘<samp><span class="samp">assert,misc,tree,gc,rtlflag,runtime</span></samp>’), ‘<samp><span class="samp">no</span></samp>’ (no checks at 946 all), ‘<samp><span class="samp">all</span></samp>’ (all but ‘<samp><span class="samp">valgrind</span></samp>’), ‘<samp><span class="samp">release</span></samp>’ (cheapest 947 checks ‘<samp><span class="samp">assert,runtime</span></samp>’) or ‘<samp><span class="samp">none</span></samp>’ (same as ‘<samp><span class="samp">no</span></samp>’). 948 Individual checks can be enabled with these flags ‘<samp><span class="samp">assert</span></samp>’, 949 ‘<samp><span class="samp">df</span></samp>’, ‘<samp><span class="samp">fold</span></samp>’, ‘<samp><span class="samp">gc</span></samp>’, ‘<samp><span class="samp">gcac</span></samp>’ ‘<samp><span class="samp">misc</span></samp>’, ‘<samp><span class="samp">rtl</span></samp>’, 950 ‘<samp><span class="samp">rtlflag</span></samp>’, ‘<samp><span class="samp">runtime</span></samp>’, ‘<samp><span class="samp">tree</span></samp>’, and ‘<samp><span class="samp">valgrind</span></samp>’. 951 952 <p>The ‘<samp><span class="samp">valgrind</span></samp>’ check requires the external <samp><span class="command">valgrind</span></samp> 953 simulator, available from <a href="http://valgrind.org/">http://valgrind.org/</a>. The 954 ‘<samp><span class="samp">df</span></samp>’, ‘<samp><span class="samp">rtl</span></samp>’, ‘<samp><span class="samp">gcac</span></samp>’ and ‘<samp><span class="samp">valgrind</span></samp>’ checks are very expensive. 955 To disable all checking, ‘<samp><span class="samp">--disable-checking</span></samp>’ or 956 ‘<samp><span class="samp">--enable-checking=none</span></samp>’ must be explicitly requested. Disabling 957 assertions will make the compiler and runtime slightly faster but 958 increase the risk of undetected internal errors causing wrong code to be 959 generated. 960 961 <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 compiler will be built with ‘<samp><span class="samp">yes</span></samp>’ checking enabled, otherwise 963 the stage1 checking flags are the same as specified by 964 <samp><span class="option">--enable-checking</span></samp>. To build the stage1 compiler with 965 different checking options use <samp><span class="option">--enable-stage1-checking</span></samp>. 966 The list of checking options is the same as for <samp><span class="option">--enable-checking</span></samp>. 967 If your system is too slow or too small to bootstrap a released compiler 968 with checking for stage1 enabled, you can use ‘<samp><span class="samp">--disable-stage1-checking</span></samp>’ 969 to disable checking for the stage1 compiler. 970 971 <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 information, every time it is run. This is for internal development 973 purposes, and only works when the compiler is being built with gcc. The 974 <var>level</var> argument controls whether the compiler is built optimized or 975 not, values are ‘<samp><span class="samp">opt</span></samp>’ and ‘<samp><span class="samp">noopt</span></samp>’. For coverage analysis you 976 want to disable optimization, for performance analysis you want to 977 enable optimization. When coverage is enabled, the default level is 978 without optimization. 979 980 <br><dt><code>--enable-gather-detailed-mem-stats</code><dd>When this option is specified more detailed information on memory 981 allocation is gathered. This information is printed when using 982 <samp><span class="option">-fmem-report</span></samp>. 983 984 <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 which lets GCC output diagnostics in languages other than American 986 English. Native Language Support is enabled by default if not doing a 987 canadian cross build. The <samp><span class="option">--disable-nls</span></samp> option disables NLS. 988 989 <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 procedure to prefer its copy of GNU <samp><span class="command">gettext</span></samp>. 991 992 <br><dt><code>--with-catgets</code><dd>If NLS is enabled, and if the host lacks <code>gettext</code> but has the 993 inferior <code>catgets</code> interface, the GCC build procedure normally 994 ignores <code>catgets</code> and instead uses GCC's copy of the GNU 995 <code>gettext</code> library. The <samp><span class="option">--with-catgets</span></samp> option causes the 996 build procedure to use the host's <code>catgets</code> in this situation. 997 998 <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 libiconv library files in <samp><var>dir</var><span class="file">/lib</span></samp>. 1000 1001 <br><dt><code>--enable-obsolete</code><dd>Enable configuration for an obsoleted system. If you attempt to 1002 configure GCC for a system (build, host, or target) which has been 1003 obsoleted, and you do not specify this flag, configure will halt with an 1004 error message. 1005 1006 <p>All support for systems which have been obsoleted in one release of GCC 1007 is removed entirely in the next major release, unless someone steps 1008 forward to maintain the port. 1009 1010 <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 that is in the IEEE 754-2008 standard. This is enabled by default only 1012 on PowerPC, i386, and x86_64 GNU/Linux systems. Other systems may also 1013 support it, but require the user to specifically enable it. You can 1014 optionally control which decimal floating point format is used (either 1015 ‘<samp><span class="samp">bid</span></samp>’ or ‘<samp><span class="samp">dpd</span></samp>’). The ‘<samp><span class="samp">bid</span></samp>’ (binary integer decimal) 1016 format is default on i386 and x86_64 systems, and the ‘<samp><span class="samp">dpd</span></samp>’ 1017 (densely packed decimal) format is default on PowerPC systems. 1018 1019 <br><dt><code>--enable-fixed-point</code><dt><code>--disable-fixed-point</code><dd>Enable (or disable) support for C fixed-point arithmetic. 1020 This option is enabled by default for some targets (such as MIPS) which 1021 have hardware-support for fixed-point operations. On other targets, you 1022 may enable this option manually. 1023 1024 <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 GNU/Linux architectures. If using <code>--without-long-double-128</code>, 1026 <code>long double</code> will be by default 64-bit, the same as <code>double</code> type. 1027 When neither of these configure options are used, the default will be 1028 128-bit <code>long double</code> when built against GNU C Library 2.4 and later, 1029 64-bit <code>long double</code> otherwise. 1030 1031 <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 library and/or the MPC library installed in a standard location and 1033 do not have their sources present in the GCC source tree then you 1034 can explicitly specify the directory where they are installed 1035 (‘<samp><span class="samp">--with-gmp=</span><var>gmpinstalldir</var></samp>’, 1036 ‘<samp><span class="samp">--with-mpfr=</span><var>mpfrinstalldir</var></samp>’, 1037 ‘<samp><span class="samp">--with-mpc=</span><var>mpcinstalldir</var></samp>’). The 1038 <samp><span class="option">--with-gmp=</span><var>gmpinstalldir</var></samp> option is shorthand for 1039 <samp><span class="option">--with-gmp-lib=</span><var>gmpinstalldir</var><span class="option">/lib</span></samp> and 1040 <samp><span class="option">--with-gmp-include=</span><var>gmpinstalldir</var><span class="option">/include</span></samp>. Likewise the 1041 <samp><span class="option">--with-mpfr=</span><var>mpfrinstalldir</var></samp> option is shorthand for 1042 <samp><span class="option">--with-mpfr-lib=</span><var>mpfrinstalldir</var><span class="option">/lib</span></samp> and 1043 <samp><span class="option">--with-mpfr-include=</span><var>mpfrinstalldir</var><span class="option">/include</span></samp>, also the 1044 <samp><span class="option">--with-mpc=</span><var>mpcinstalldir</var></samp> option is shorthand for 1045 <samp><span class="option">--with-mpc-lib=</span><var>mpcinstalldir</var><span class="option">/lib</span></samp> and 1046 <samp><span class="option">--with-mpc-include=</span><var>mpcinstalldir</var><span class="option">/include</span></samp>. If these 1047 shorthand assumptions are not correct, you can use the explicit 1048 include and lib options directly. You might also need to ensure the 1049 shared libraries can be found by the dynamic linker when building and 1050 using GCC, for example by setting the runtime shared library path 1051 variable (<samp><span class="env">LD_LIBRARY_PATH</span></samp> on GNU/Linux and Solaris systems). 1052 1053 <p>These flags are applicable to the host platform only. When building 1054 a cross compiler, they will not be used to configure target libraries. 1055 1056 <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 want to build GCC, you can explicitly specify the directory where it is 1058 installed (‘<samp><span class="samp">--with-isl=</span><var>islinstalldir</var></samp>’). The 1059 <samp><span class="option">--with-isl=</span><var>islinstalldir</var></samp> option is shorthand for 1060 <samp><span class="option">--with-isl-lib=</span><var>islinstalldir</var><span class="option">/lib</span></samp> and 1061 <samp><span class="option">--with-isl-include=</span><var>islinstalldir</var><span class="option">/include</span></samp>. If this 1062 shorthand assumption is not correct, you can use the explicit 1063 include and lib options directly. 1064 1065 <p>These flags are applicable to the host platform only. When building 1066 a cross compiler, they will not be used to configure target libraries. 1067 1068 <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 to specify how the linker should find the standard C++ library used 1070 internally by PPL. Typical values of <var>linker-args</var> might be 1071 ‘<samp><span class="samp">-lstdc++</span></samp>’ or ‘<samp><span class="samp">-Wl,-Bstatic,-lstdc++,-Bdynamic -lm</span></samp>’. If you are 1072 linking with a shared copy of PPL, you probably do not need this 1073 option; shared library dependencies will cause the linker to search 1074 for the standard C++ library automatically. 1075 1076 <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 stage 1 of GCC. These are also used when linking GCC if configured with 1078 <samp><span class="option">--disable-bootstrap</span></samp>. By default no special flags are used. 1079 1080 <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 of GCC. These are also used when linking GCC if configured with 1082 <samp><span class="option">--disable-bootstrap</span></samp>. The default is the argument to 1083 <samp><span class="option">--with-host-libstdcxx</span></samp>, if specified. 1084 1085 <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 stage 2 and later when bootstrapping GCC. If neither –with-boot-libs 1087 nor –with-host-libstdcxx is set to a value, then the default is 1088 ‘<samp><span class="samp">-static-libstdc++ -static-libgcc</span></samp>’. 1089 1090 <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 and later when bootstrapping GCC. The default is the argument to 1092 <samp><span class="option">--with-host-libstdcxx</span></samp>, if specified. 1093 1094 <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 building runtime libraries. ‘<samp><var>map</var></samp>’ is a space-separated 1096 list of maps of the form ‘<samp><var>old</var><span class="samp">=</span><var>new</var></samp>’. 1097 1098 <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 links (links performed without the <samp><span class="option">-r</span></samp> or <samp><span class="option">--relocatable</span></samp> 1100 option), if the linker supports it. If you specify 1101 <samp><span class="option">--enable-linker-build-id</span></samp>, but your linker does not 1102 support <samp><span class="option">--build-id</span></samp> option, a warning is issued and the 1103 <samp><span class="option">--enable-linker-build-id</span></samp> option is ignored. The default is off. 1104 1105 <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 linker for all final links. <var>choice</var> can be one of 1107 ‘<samp><span class="samp">sysv</span></samp>’, ‘<samp><span class="samp">gnu</span></samp>’, and ‘<samp><span class="samp">both</span></samp>’ where ‘<samp><span class="samp">sysv</span></samp>’ is the default. 1108 1109 <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 static data members and inline function local statics. Enabled by 1111 default for a toolchain with an assembler that accepts it and 1112 GLIBC 2.11 or above, otherwise disabled. 1113 1114 <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 option (if not used explicitly on the command line). <var>choice</var> 1116 can be one of ‘<samp><span class="samp">never</span></samp>’, ‘<samp><span class="samp">auto</span></samp>’, ‘<samp><span class="samp">always</span></samp>’, and ‘<samp><span class="samp">auto-if-env</span></samp>’ 1117 where ‘<samp><span class="samp">auto</span></samp>’ is the default. ‘<samp><span class="samp">auto-if-env</span></samp>’ means that 1118 <samp><span class="option">-fdiagnostics-color=auto</span></samp> will be the default if <code>GCC_COLORS</code> 1119 is present and non-empty in the environment, and 1120 <samp><span class="option">-fdiagnostics-color=never</span></samp> otherwise. 1121 1122 <br><dt><code>--enable-lto</code><dt><code>--disable-lto</code><dd>Enable support for link-time optimization (LTO). This is enabled by 1123 default, and may be disabled using <samp><span class="option">--disable-lto</span></samp>. 1124 1125 <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 host system architecture. For the case that the linker has a 1127 different (but run-time compatible) architecture, these flags can be 1128 specified to build plugins that are compatible to the linker. For 1129 example, if you are building GCC for a 64-bit x86_64 1130 (‘<samp><span class="samp">x86_64-unknown-linux-gnu</span></samp>’) host system, but have a 32-bit x86 1131 GNU/Linux (‘<samp><span class="samp">i686-pc-linux-gnu</span></samp>’) linker executable (which is 1132 executable on the former system), you can configure GCC as follows for 1133 getting compatible linker plugins: 1134 1135 <pre class="smallexample"> % <var>srcdir</var>/configure \ 1136 --host=x86_64-unknown-linux-gnu \ 1137 --enable-linker-plugin-configure-flags=--host=i686-pc-linux-gnu \ 1138 --enable-linker-plugin-flags='CC=gcc\ -m32\ -Wl,-rpath,[...]/i686-pc-linux-gnu/lib' 1139 </pre> 1140 <br><dt><code>--with-plugin-ld=</code><var>pathname</var><dd>Enable an alternate linker to be used at link-time optimization (LTO) 1141 link time when <samp><span class="option">-fuse-linker-plugin</span></samp> is enabled. 1142 This linker should have plugin support such as gold starting with 1143 version 2.20 or GNU ld starting with version 2.21. 1144 See <samp><span class="option">-fuse-linker-plugin</span></samp> for details. 1145 1146 <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 produce shorter header file paths in diagnostics and dependency output 1148 files, but these changed header paths may conflict with some compilation 1149 environments. Enabled by default, and may be disabled using 1150 <samp><span class="option">--disable-canonical-system-headers</span></samp>. 1151 1152 <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 will be version <var>major</var>.<var>minor</var> or later. Normally this can 1154 be detected from the C library's header files, but this option may be 1155 needed when bootstrapping a cross toolchain without the header files 1156 available for building the initial bootstrap compiler. 1157 1158 <p>If GCC is configured with some multilibs that use glibc and some that 1159 do not, this option applies only to the multilibs that use glibc. 1160 However, such configurations may not work well as not all the relevant 1161 configuration in GCC is on a per-multilib basis. 1162 1163 <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 1165 <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 Offload compilers are expected to be already installed. Default search 1167 path for them is <samp><var>exec-prefix</var></samp>, but it can be changed by 1168 specifying paths <var>path1</var>, <small class="dots">...</small>, <var>pathN</var>. 1169 1170 <pre class="smallexample"> % <var>srcdir</var>/configure \ 1171 --enable-offload-target=i686-unknown-linux-gnu=/path/to/i686/compiler,x86_64-pc-linux-gnu 1172 </pre> 1173 </dl> 1174 1175 <h4 class="subheading"><a name="TOC3"></a>Cross-Compiler-Specific Options</h4> 1176 1177 <p>The following options only apply to building cross compilers. 1178 1179 <dl> 1180 <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 (a subset of) the root filesystem of the target operating system. 1182 Target system headers, libraries and run-time object files will be 1183 searched for in there. More specifically, this acts as if 1184 <samp><span class="option">--sysroot=</span><var>dir</var></samp> was added to the default options of the built 1185 compiler. The specified directory is not copied into the 1186 install tree, unlike the options <samp><span class="option">--with-headers</span></samp> and 1187 <samp><span class="option">--with-libs</span></samp> that this option obsoletes. The default value, 1188 in case <samp><span class="option">--with-sysroot</span></samp> is not given an argument, is 1189 <samp><span class="option">${gcc_tooldir}/sys-root</span></samp>. If the specified directory is a 1190 subdirectory of <samp><span class="option">${exec_prefix}</span></samp>, then it will be found relative to 1191 the GCC binaries if the installation tree is moved. 1192 1193 <p>This option affects the system root for the compiler used to build 1194 target libraries (which runs on the build system) and the compiler newly 1195 installed with <code>make install</code>; it does not affect the compiler which is 1196 used to build GCC itself. 1197 1198 <p>If you specify the <samp><span class="option">--with-native-system-header-dir=</span><var>dirname</var></samp> 1199 option then the compiler will search that directory within <var>dirname</var> for 1200 native system headers rather than the default <samp><span class="file">/usr/include</span></samp>. 1201 1202 <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 <samp><span class="option">--with-sysroot</span></samp>) while building target libraries, instead of 1204 the directory specified with <samp><span class="option">--with-sysroot</span></samp>. This option is 1205 only useful when you are already using <samp><span class="option">--with-sysroot</span></samp>. You 1206 can use <samp><span class="option">--with-build-sysroot</span></samp> when you are configuring with 1207 <samp><span class="option">--prefix</span></samp> set to a directory that is different from the one in 1208 which you are installing GCC and your target libraries. 1209 1210 <p>This option affects the system root for the compiler used to build 1211 target libraries (which runs on the build system); it does not affect 1212 the compiler which is used to build GCC itself. 1213 1214 <p>If you specify the <samp><span class="option">--with-native-system-header-dir=</span><var>dirname</var></samp> 1215 option then the compiler will search that directory within <var>dirname</var> for 1216 native system headers rather than the default <samp><span class="file">/usr/include</span></samp>. 1217 1218 <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 Specifies that target headers are available when building a cross compiler. 1220 The <var>dir</var> argument specifies a directory which has the target include 1221 files. These include files will be copied into the <samp><span class="file">gcc</span></samp> install 1222 directory. <em>This option with the </em><var>dir</var><em> argument is required</em> when 1223 building a cross compiler, if <samp><var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span></samp> 1224 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 pre-exist, the <var>dir</var> argument may be omitted. <samp><span class="command">fixincludes</span></samp> 1226 will be run on these files to make them compatible with GCC. 1227 1228 <br><dt><code>--without-headers</code><dd>Tells GCC not use any target headers from a libc when building a cross 1229 compiler. When crossing to GNU/Linux, you need the headers so GCC 1230 can build the exception handling for libgcc. 1231 1232 <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 Specifies a list of directories which contain the target runtime 1234 libraries. These libraries will be copied into the <samp><span class="file">gcc</span></samp> install 1235 directory. If the directory list is omitted, this option has no 1236 effect. 1237 1238 <br><dt><code>--with-newlib</code><dd>Specifies that ‘<samp><span class="samp">newlib</span></samp>’ is 1239 being used as the target C library. This causes <code>__eprintf</code> to be 1240 omitted from <samp><span class="file">libgcc.a</span></samp> on the assumption that it will be provided by 1241 ‘<samp><span class="samp">newlib</span></samp>’. 1242 1243 <br><dt><code>--with-avrlibc</code><dd>Specifies that ‘<samp><span class="samp">AVR-Libc</span></samp>’ is 1244 being used as the target C library. This causes float support 1245 functions like <code>__addsf3</code> to be omitted from <samp><span class="file">libgcc.a</span></samp> on 1246 the assumption that it will be provided by <samp><span class="file">libm.a</span></samp>. For more 1247 technical details, cf. <a href="http://gcc.gnu.org/PR54461">PR54461</a>. 1248 This option is only supported for the AVR target. It is not supported for 1249 RTEMS configurations, which currently use newlib. The option is 1250 supported since version 4.7.2 and is the default in 4.8.0 and newer. 1251 1252 <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 Currently, the valid <var>library</var> is ‘<samp><span class="samp">newlib</span></samp>’ or ‘<samp><span class="samp">mculib</span></samp>’. 1254 This option is only supported for the NDS32 target. 1255 1256 <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 that will be used while building GCC itself. This option can be useful 1258 if the directory layouts are different between the system you are building 1259 GCC on, and the system where you will deploy it. 1260 1261 <p>For example, on an ‘<samp><span class="samp">ia64-hp-hpux</span></samp>’ system, you may have the GNU 1262 assembler and linker in <samp><span class="file">/usr/bin</span></samp>, and the native tools in a 1263 different path, and build a toolchain that expects to find the 1264 native tools in <samp><span class="file">/usr/bin</span></samp>. 1265 1266 <p>When you use this option, you should ensure that <var>dir</var> includes 1267 <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 <samp><span class="command">ranlib</span></samp> and <samp><span class="command">strip</span></samp> if necessary, and possibly 1269 <samp><span class="command">objdump</span></samp>. Otherwise, GCC may use an inconsistent set of 1270 tools. 1271 </dl> 1272 1273 <h4 class="subheading"><a name="TOC4"></a>Java-Specific Options</h4> 1274 1275 <p>The following option applies to the build of the Java front end. 1276 1277 <dl> 1278 <dt><code>--disable-libgcj</code><dd>Specify that the run-time libraries 1279 used by GCJ should not be built. This is useful in case you intend 1280 to use GCJ with some other run-time, or you're going to install it 1281 separately, or it just happens not to build on your particular 1282 machine. In general, if the Java front end is enabled, the GCJ 1283 libraries will be enabled too, unless they're known to not work on 1284 the target platform. If GCJ is enabled but ‘<samp><span class="samp">libgcj</span></samp>’ isn't built, you 1285 may need to port it; in this case, before modifying the top-level 1286 <samp><span class="file">configure.in</span></samp> so that ‘<samp><span class="samp">libgcj</span></samp>’ is enabled by default on this platform, 1287 you may use <samp><span class="option">--enable-libgcj</span></samp> to override the default. 1288 1289 </dl> 1290 1291 <p>The following options apply to building ‘<samp><span class="samp">libgcj</span></samp>’. 1292 1293 <h5 class="subsubheading"><a name="TOC5"></a>General Options</h5> 1294 1295 <dl> 1296 <dt><code>--enable-java-maintainer-mode</code><dd>By default the ‘<samp><span class="samp">libjava</span></samp>’ build will not attempt to compile the 1297 <samp><span class="file">.java</span></samp> source files to <samp><span class="file">.class</span></samp>. Instead, it will use the 1298 <samp><span class="file">.class</span></samp> files from the source tree. If you use this option you 1299 must have executables named <samp><span class="command">ecj1</span></samp> and <samp><span class="command">gjavah</span></samp> in your path 1300 for use by the build. You must use this option if you intend to 1301 modify any <samp><span class="file">.java</span></samp> files in <samp><span class="file">libjava</span></samp>. 1302 1303 <br><dt><code>--with-java-home=</code><var>dirname</var><dd>This ‘<samp><span class="samp">libjava</span></samp>’ option overrides the default value of the 1304 ‘<samp><span class="samp">java.home</span></samp>’ system property. It is also used to set 1305 ‘<samp><span class="samp">sun.boot.class.path</span></samp>’ to <samp><var>dirname</var><span class="file">/lib/rt.jar</span></samp>. By 1306 default ‘<samp><span class="samp">java.home</span></samp>’ is set to <samp><var>prefix</var></samp> and 1307 ‘<samp><span class="samp">sun.boot.class.path</span></samp>’ to 1308 <samp><var>datadir</var><span class="file">/java/libgcj-</span><var>version</var><span class="file">.jar</span></samp>. 1309 1310 <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 file containing the Eclipse Java compiler. A specially modified 1312 version of this compiler is used by <samp><span class="command">gcj</span></samp> to parse 1313 <samp><span class="file">.java</span></samp> source files. If this option is given, the 1314 ‘<samp><span class="samp">libjava</span></samp>’ build will create and install an <samp><span class="file">ecj1</span></samp> executable 1315 which uses this jar file at runtime. 1316 1317 <p>If this option is not given, but an <samp><span class="file">ecj.jar</span></samp> file is found in 1318 the topmost source tree at configure time, then the ‘<samp><span class="samp">libgcj</span></samp>’ 1319 build will create and install <samp><span class="file">ecj1</span></samp>, and will also install the 1320 discovered <samp><span class="file">ecj.jar</span></samp> into a suitable place in the install tree. 1321 1322 <p>If <samp><span class="file">ecj1</span></samp> is not installed, then the user will have to supply one 1323 on his path in order for <samp><span class="command">gcj</span></samp> to properly parse <samp><span class="file">.java</span></samp> 1324 source files. A suitable jar is available from 1325 <a href="ftp://sourceware.org/pub/java/">ftp://sourceware.org/pub/java/</a>. 1326 1327 <br><dt><code>--disable-getenv-properties</code><dd>Don't set system properties from <samp><span class="env">GCJ_PROPERTIES</span></samp>. 1328 1329 <br><dt><code>--enable-hash-synchronization</code><dd>Use a global hash table for monitor locks. Ordinarily, 1330 ‘<samp><span class="samp">libgcj</span></samp>’'s ‘<samp><span class="samp">configure</span></samp>’ script automatically makes 1331 the correct choice for this option for your platform. Only use 1332 this if you know you need the library to be configured differently. 1333 1334 <br><dt><code>--enable-interpreter</code><dd>Enable the Java interpreter. The interpreter is automatically 1335 enabled by default on all platforms that support it. This option 1336 is really only useful if you want to disable the interpreter 1337 (using <samp><span class="option">--disable-interpreter</span></samp>). 1338 1339 <br><dt><code>--disable-java-net</code><dd>Disable java.net. This disables the native part of java.net only, 1340 using non-functional stubs for native method implementations. 1341 1342 <br><dt><code>--disable-jvmpi</code><dd>Disable JVMPI support. 1343 1344 <br><dt><code>--disable-libgcj-bc</code><dd>Disable BC ABI compilation of certain parts of libgcj. By default, 1345 some portions of libgcj are compiled with <samp><span class="option">-findirect-dispatch</span></samp> 1346 and <samp><span class="option">-fno-indirect-classes</span></samp>, allowing them to be overridden at 1347 run-time. 1348 1349 <p>If <samp><span class="option">--disable-libgcj-bc</span></samp> is specified, libgcj is built without 1350 these options. This allows the compile-time linker to resolve 1351 dependencies when statically linking to libgcj. However it makes it 1352 impossible to override the affected portions of libgcj at run-time. 1353 1354 <br><dt><code>--enable-reduced-reflection</code><dd>Build most of libgcj with <samp><span class="option">-freduced-reflection</span></samp>. This reduces 1355 the size of libgcj at the expense of not being able to do accurate 1356 reflection on the classes it contains. This option is safe if you 1357 know that code using libgcj will never use reflection on the standard 1358 runtime classes in libgcj (including using serialization, RMI or CORBA). 1359 1360 <br><dt><code>--with-ecos</code><dd>Enable runtime eCos target support. 1361 1362 <br><dt><code>--without-libffi</code><dd>Don't use ‘<samp><span class="samp">libffi</span></samp>’. This will disable the interpreter and JNI 1363 support as well, as these require ‘<samp><span class="samp">libffi</span></samp>’ to work. 1364 1365 <br><dt><code>--enable-libgcj-debug</code><dd>Enable runtime debugging code. 1366 1367 <br><dt><code>--enable-libgcj-multifile</code><dd>If specified, causes all <samp><span class="file">.java</span></samp> source files to be 1368 compiled into <samp><span class="file">.class</span></samp> files in one invocation of 1369 ‘<samp><span class="samp">gcj</span></samp>’. This can speed up build time, but is more 1370 resource-intensive. If this option is unspecified or 1371 disabled, ‘<samp><span class="samp">gcj</span></samp>’ is invoked once for each <samp><span class="file">.java</span></samp> 1372 file to compile into a <samp><span class="file">.class</span></samp> file. 1373 1374 <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 1376 <br><dt><code>--enable-sjlj-exceptions</code><dd>Force use of the <code>setjmp</code>/<code>longjmp</code>-based scheme for exceptions. 1377 ‘<samp><span class="samp">configure</span></samp>’ ordinarily picks the correct value based on the platform. 1378 Only use this option if you are sure you need a different setting. 1379 1380 <br><dt><code>--with-system-zlib</code><dd>Use installed ‘<samp><span class="samp">zlib</span></samp>’ rather than that included with GCC. 1381 1382 <br><dt><code>--with-win32-nlsapi=ansi, unicows or unicode</code><dd>Indicates how MinGW ‘<samp><span class="samp">libgcj</span></samp>’ translates between UNICODE 1383 characters and the Win32 API. 1384 1385 <br><dt><code>--enable-java-home</code><dd>If enabled, this creates a JPackage compatible SDK environment during install. 1386 Note that if –enable-java-home is used, –with-arch-directory=ARCH must also 1387 be specified. 1388 1389 <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 environment created when –enable-java-home is passed. Typical names for this 1391 directory include i386, amd64, ia64, etc. 1392 1393 <br><dt><code>--with-os-directory=DIR</code><dd>Specifies the OS directory for the SDK include directory. This is set to auto 1394 detect, and is typically 'linux'. 1395 1396 <br><dt><code>--with-origin-name=NAME</code><dd>Specifies the JPackage origin name. This defaults to the 'gcj' in 1397 java-1.5.0-gcj. 1398 1399 <br><dt><code>--with-arch-suffix=SUFFIX</code><dd>Specifies the suffix for the sdk directory. Defaults to the empty string. 1400 Examples include '.x86_64' in 'java-1.5.0-gcj-1.5.0.0.x86_64'. 1401 1402 <br><dt><code>--with-jvm-root-dir=DIR</code><dd>Specifies where to install the SDK. Default is $(prefix)/lib/jvm. 1403 1404 <br><dt><code>--with-jvm-jar-dir=DIR</code><dd>Specifies where to install jars. Default is $(prefix)/lib/jvm-exports. 1405 1406 <br><dt><code>--with-python-dir=DIR</code><dd>Specifies where to install the Python modules used for aot-compile. DIR should 1407 not include the prefix used in installation. For example, if the Python modules 1408 are to be installed in /usr/lib/python2.5/site-packages, then 1409 –with-python-dir=/lib/python2.5/site-packages should be passed. If this is 1410 not specified, then the Python modules are installed in $(prefix)/share/python. 1411 1412 <br><dt><code>--enable-aot-compile-rpm</code><dd>Adds aot-compile-rpm to the list of installed scripts. 1413 1414 <br><dt><code>--enable-browser-plugin</code><dd>Build the gcjwebplugin web browser plugin. 1415 1416 <br><dt><code>--enable-static-libjava</code><dd>Build static libraries in libjava. The default is to only build shared 1417 libraries. 1418 1419 <dl> 1420 <dt><code>ansi</code><dd>Use the single-byte <code>char</code> and the Win32 A functions natively, 1421 translating to and from UNICODE when using these functions. If 1422 unspecified, this is the default. 1423 1424 <br><dt><code>unicows</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively. Adds 1425 <code>-lunicows</code> to <samp><span class="file">libgcj.spec</span></samp> to link with ‘<samp><span class="samp">libunicows</span></samp>’. 1426 <samp><span class="file">unicows.dll</span></samp> needs to be deployed on Microsoft Windows 9X machines 1427 running built executables. <samp><span class="file">libunicows.a</span></samp>, an open-source 1428 import library around Microsoft's <code>unicows.dll</code>, is obtained from 1429 <a href="http://libunicows.sourceforge.net/">http://libunicows.sourceforge.net/</a>, which also gives details 1430 on getting <samp><span class="file">unicows.dll</span></samp> from Microsoft. 1431 1432 <br><dt><code>unicode</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively. Does <em>not</em> 1433 add <code>-lunicows</code> to <samp><span class="file">libgcj.spec</span></samp>. The built executables will 1434 only run on Microsoft Windows NT and above. 1435 </dl> 1436 </dl> 1437 1438 <h5 class="subsubheading"><a name="TOC6"></a>AWT-Specific Options</h5> 1439 1440 <dl> 1441 <dt><code>--with-x</code><dd>Use the X Window System. 1442 1443 <br><dt><code>--enable-java-awt=PEER(S)</code><dd>Specifies the AWT peer library or libraries to build alongside 1444 ‘<samp><span class="samp">libgcj</span></samp>’. If this option is unspecified or disabled, AWT 1445 will be non-functional. Current valid values are <samp><span class="option">gtk</span></samp> and 1446 <samp><span class="option">xlib</span></samp>. Multiple libraries should be separated by a 1447 comma (i.e. <samp><span class="option">--enable-java-awt=gtk,xlib</span></samp>). 1448 1449 <br><dt><code>--enable-gtk-cairo</code><dd>Build the cairo Graphics2D implementation on GTK. 1450 1451 <br><dt><code>--enable-java-gc=TYPE</code><dd>Choose garbage collector. Defaults to <samp><span class="option">boehm</span></samp> if unspecified. 1452 1453 <br><dt><code>--disable-gtktest</code><dd>Do not try to compile and run a test GTK+ program. 1454 1455 <br><dt><code>--disable-glibtest</code><dd>Do not try to compile and run a test GLIB program. 1456 1457 <br><dt><code>--with-libart-prefix=PFX</code><dd>Prefix where libart is installed (optional). 1458 1459 <br><dt><code>--with-libart-exec-prefix=PFX</code><dd>Exec prefix where libart is installed (optional). 1460 1461 <br><dt><code>--disable-libarttest</code><dd>Do not try to compile and run a test libart program. 1462 1463 </dl> 1464 1465 <h5 class="subsubheading"><a name="TOC7"></a>Overriding <samp><span class="command">configure</span></samp> test results</h5> 1466 1467 <p>Sometimes, it might be necessary to override the result of some 1468 <samp><span class="command">configure</span></samp> test, for example in order to ease porting to a new 1469 system or work around a bug in a test. The toplevel <samp><span class="command">configure</span></samp> 1470 script provides three variables for this: 1471 1472 <dl> 1473 <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 scripts. 1475 1476 <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 scripts. 1478 1479 <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 scripts. 1481 1482 </dl> 1483 1484 <p>In order to avoid shell and <samp><span class="command">make</span></samp> quoting issues for complex 1485 overrides, you can pass a setting for <samp><span class="env">CONFIG_SITE</span></samp> and set 1486 variables in the site file. 1487 1488 <p><hr /> 1489 <p><a href="./index.html">Return to the GCC Installation page</a> 1490 1491 <!-- ***Building**************************************************************** --> 1492 <!-- ***Testing***************************************************************** --> 1493 <!-- ***Final install*********************************************************** --> 1494 <!-- ***Binaries**************************************************************** --> 1495 <!-- ***Specific**************************************************************** --> 1496 <!-- ***Old documentation****************************************************** --> 1497 <!-- ***GFDL******************************************************************** --> 1498 <!-- *************************************************************************** --> 1499 <!-- Part 6 The End of the Document --> 1500 </body></html> 1501 1502
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