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      1 # GCC_NO_EXECUTABLES
      2 # -----------------
      3 # FIXME: The GCC team has specific needs which the current Autoconf
      4 # framework cannot solve elegantly.  This macro implements a dirty
      5 # hack until Autoconf is able to provide the services its users
      6 # need.
      7 #
      8 # Several of the support libraries that are often built with GCC can't
      9 # assume the tool-chain is already capable of linking a program: the
     10 # compiler often expects to be able to link with some of such
     11 # libraries.
     12 #
     13 # In several of these libraries, workarounds have been introduced to
     14 # avoid the AC_PROG_CC_WORKS test, that would just abort their
     15 # configuration.  The introduction of AC_EXEEXT, enabled either by
     16 # libtool or by CVS autoconf, have just made matters worse.
     17 #
     18 # Unlike the previous AC_NO_EXECUTABLES, this test does not
     19 # disable link tests at autoconf time, but at configure time.
     20 # This allows AC_NO_EXECUTABLES to be invoked conditionally.
     21 AC_DEFUN_ONCE([GCC_NO_EXECUTABLES],
     22 [m4_divert_push([KILL])
     23 
     24 AC_BEFORE([$0], [_AC_COMPILER_EXEEXT])
     25 AC_BEFORE([$0], [AC_LINK_IFELSE])
     26 
     27 m4_define([_AC_COMPILER_EXEEXT],
     28 [AC_LANG_CONFTEST([AC_LANG_PROGRAM(
     29 		     [#include <stdio.h>],
     30 		     [printf ("hello world\n");])])
     31 # FIXME: Cleanup?
     32 AS_IF([AC_TRY_EVAL(ac_link)], [gcc_no_link=no], [gcc_no_link=yes])
     33 if test x$gcc_no_link = xyes; then
     34   # Setting cross_compile will disable run tests; it will
     35   # also disable AC_CHECK_FILE but that's generally
     36   # correct if we can't link.
     37   cross_compiling=yes
     38   EXEEXT=
     39 else
     40   ]m4_defn([_AC_COMPILER_EXEEXT])dnl
     41 fi
     42 )
     43 
     44 m4_define([AC_LINK_IFELSE],
     45 if test x$gcc_no_link = xyes; then
     46   AC_MSG_ERROR([Link tests are not allowed after [[$0]].])
     47 fi
     48 m4_defn([AC_LINK_IFELSE]))
     49 
     50 dnl This is a shame.  We have to provide a default for some link tests,
     51 dnl similar to the default for run tests.
     52 m4_define([AC_FUNC_MMAP],
     53 if test x$gcc_no_link = xyes; then
     54   if test "x${ac_cv_func_mmap_fixed_mapped+set}" != xset; then
     55     ac_cv_func_mmap_fixed_mapped=no
     56   fi
     57 fi
     58 if test "x${ac_cv_func_mmap_fixed_mapped}" != xno; then
     59   m4_defn([AC_FUNC_MMAP])
     60 fi)
     61 
     62 m4_divert_pop()dnl
     63 ])# GCC_NO_EXECUTABLES
     64 
     65 # Use the strongest available test out of AC_TRY_COMPILE and AC_TRY_LINK.
     66 AC_DEFUN([GCC_TRY_COMPILE_OR_LINK],
     67 [if test x$gcc_no_link = xyes; then
     68   AC_TRY_COMPILE([$1], [$2], [$3], [$4])
     69 else
     70   AC_TRY_LINK([$1], [$2], [$3], [$4])
     71 fi])
     72