m4/ax_ld_check_flag.m4

   1 # ===========================================================================
   2 #     http://www.gnu.org/software/autoconf-archive/ax_ld_check_flag.html
   3 # ===========================================================================
   4 #
   5 # SYNOPSIS
   6 #
   7 #   AX_LDFLAGS_OPTION(FLAG-TO-CHECK,[VAR],[NOTFOUND])
   8 #
   9 # DESCRIPTION
  10 #
  11 #   This macro tests if the C compiler supports the flag FLAG-TO-CHECK. If
  12 #   successfull add it to VAR.
  13 #
  14 #   This code is inspired from KDE_CHECK_COMPILER_FLAG macro. Thanks to
  15 #   Bogdan Drozdowski <bogdandr@op.pl> for testing and bug fixes.
  16 #
  17 #   This version has been (heavily) modified by Vincent Bernat
  18 #   <bernat@luffy.cx> to match AX_CFLAGS_GCC_OPTION.
  19 #
  20 # LICENSE
  21 #
  22 #   Copyright (c) 2008 Francesco Salvestrini <salvestrini@users.sourceforge.net>
  23 #
  24 #   This program is free software; you can redistribute it and/or modify it
  25 #   under the terms of the GNU General Public License as published by the
  26 #   Free Software Foundation; either version 2 of the License, or (at your
  27 #   option) any later version.
  28 #
  29 #   This program is distributed in the hope that it will be useful, but
  30 #   WITHOUT ANY WARRANTY; without even the implied warranty of
  31 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
  32 #   Public License for more details.
  33 #
  34 #   You should have received a copy of the GNU General Public License along
  35 #   with this program. If not, see <http://www.gnu.org/licenses/>.
  36 #
  37 #   As a special exception, the respective Autoconf Macro's copyright owner
  38 #   gives unlimited permission to copy, distribute and modify the configure
  39 #   scripts that are the output of Autoconf when processing the Macro. You
  40 #   need not follow the terms of the GNU General Public License when using
  41 #   or distributing such scripts, even though portions of the text of the
  42 #   Macro appear in them. The GNU General Public License (GPL) does govern
  43 #   all other use of the material that constitutes the Autoconf Macro.
  44 #
  45 #   This special exception to the GPL applies to versions of the Autoconf
  46 #   Macro released by the Autoconf Archive. When you make and distribute a
  47 #   modified version of the Autoconf Macro, you may extend this special
  48 #   exception to the GPL to apply to your modified version as well.
  49
  50 #serial 6
  51
  52 AC_DEFUN([AX_LDFLAGS_OPTION],[
  53   AC_PREREQ([2.61])
  54   AC_REQUIRE([AC_PROG_SED])
  55
  56   flag=`echo "$1" | $SED 'y% .=/+-(){}<>:*,%_______________%'`
  57
  58   AC_CACHE_CHECK([whether the linker accepts the $1 flag],
  59     [ax_cv_ld_check_flag_$flag],[
  60
  61     AC_LANG_SAVE
  62     AC_LANG_C
  63
  64     save_LDFLAGS="$LDFLAGS"
  65     LDFLAGS="-Werror $LDFLAGS $[]m4_ifval($2,$2,) $1"
  66     AC_LINK_IFELSE([
  67       AC_LANG_PROGRAM([],[])
  68     ],[
  69       eval "ax_cv_ld_check_flag_$flag=yes"
  70     ],[
  71       eval "ax_cv_ld_check_flag_$flag=no"
  72     ])
  73
  74     LDFLAGS="$save_LDFLAGS"
  75
  76     AC_LANG_RESTORE
  77
  78   ])
  79
  80   AS_IF([eval "test \"`echo '$ax_cv_ld_check_flag_'$flag`\" = yes"],[
  81     m4_ifval($2,$2,LDFLAGS)="$[]m4_ifval($2,$2,LDFLAGS) $1"
  82   ],[
  83     :; $3
  84   ])
  85 ])