m4/ax_cflags_gcc_option.m4

   1 # ===========================================================================
   2 #          http://autoconf-archive.cryp.to/ax_cflags_gcc_option.html
   3 # ===========================================================================
   4 #
   5 # SYNOPSIS
   6 #
   7 #   AX_CFLAGS_GCC_OPTION (optionflag [,[shellvar][,[A][,[NA]]])
   8 #
   9 # DESCRIPTION
  10 #
  11 #   AX_CFLAGS_GCC_OPTION(-fvomit-frame) would show a message as like
  12 #   "checking CFLAGS for gcc -fvomit-frame ... yes" and adds the optionflag
  13 #   to CFLAGS if it is understood. You can override the shellvar-default of
  14 #   CFLAGS of course. The order of arguments stems from the explicit macros
  15 #   like AX_CFLAGS_WARN_ALL.
  16 #
  17 #   The cousin AX_CXXFLAGS_GCC_OPTION would check for an option to add to
  18 #   CXXFLAGS - and it uses the autoconf setup for C++ instead of C (since it
  19 #   is possible to use different compilers for C and C++).
  20 #
  21 #   The macro is a lot simpler than any special AX_CFLAGS_* macro (or
  22 #   ac_cxx_rtti.m4 macro) but allows to check for arbitrary options.
  23 #   However, if you use this macro in a few places, it would be great if you
  24 #   would make up a new function-macro and submit it to the ac-archive.
  25 #
  26 #     - $1 option-to-check-for : required ("-option" as non-value)
  27 #     - $2 shell-variable-to-add-to : CFLAGS (or CXXFLAGS in the other case)
  28 #     - $3 action-if-found : add value to shellvariable
  29 #     - $4 action-if-not-found : nothing
  30 #
  31 #   There are other variants that emerged from the original macro variant
  32 #   which did just test an option to be possibly added. However, some
  33 #   compilers accept an option silently, or possibly for just another option
  34 #   that was not intended. Therefore, we have to do a generic test for a
  35 #   compiler family. For gcc we check "-pedantic" being accepted which is
  36 #   also understood by compilers who just want to be compatible with gcc
  37 #   even when not being made from gcc sources.
  38 #
  39 #   This version has been modified by Vincent Bernat <bernat@luffy.cx>
  40 #   to ensure that the shell variable the option is added to is
  41 #   prepended to the test variable (like a regular CFLAGS).
  42 #
  43 #   See also: AX_CFLAGS_SUN_OPTION, AX_CFLAGS_HPUX_OPTION,
  44 #   AX_CFLAGS_AIX_OPTION, and AX_CFLAGS_IRIX_OPTION.
  45 #
  46 # LICENSE
  47 #
  48 #   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
  49 #
  50 #   This program is free software; you can redistribute it and/or modify it
  51 #   under the terms of the GNU General Public License as published by the
  52 #   Free Software Foundation; either version 2 of the License, or (at your
  53 #   option) any later version.
  54 #
  55 #   This program is distributed in the hope that it will be useful, but
  56 #   WITHOUT ANY WARRANTY; without even the implied warranty of
  57 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
  58 #   Public License for more details.
  59 #
  60 #   You should have received a copy of the GNU General Public License along
  61 #   with this program. If not, see <http://www.gnu.org/licenses/>.
  62 #
  63 #   As a special exception, the respective Autoconf Macro's copyright owner
  64 #   gives unlimited permission to copy, distribute and modify the configure
  65 #   scripts that are the output of Autoconf when processing the Macro. You
  66 #   need not follow the terms of the GNU General Public License when using
  67 #   or distributing such scripts, even though portions of the text of the
  68 #   Macro appear in them. The GNU General Public License (GPL) does govern
  69 #   all other use of the material that constitutes the Autoconf Macro.
  70 #
  71 #   This special exception to the GPL applies to versions of the Autoconf
  72 #   Macro released by the Autoconf Archive. When you make and distribute a
  73 #   modified version of the Autoconf Macro, you may extend this special
  74 #   exception to the GPL to apply to your modified version as well.
  75
  76 dnl -------------------------------------------------------------------------
  77
  78 AC_DEFUN([AX_CFLAGS_GCC_OPTION], [dnl
  79 AS_VAR_PUSHDEF([FLAGS],[CFLAGS])dnl
  80 AS_VAR_PUSHDEF([VAR],[ac_cv_cflags_gcc_option_$1])dnl
  81 AC_CACHE_CHECK([FLAGS for gcc m4_ifval($1,$1,-option)],
  82 VAR,[AS_VAR_SET([VAR],["no, unknown"])
  83  AC_LANG_SAVE
  84  AC_LANG_C
  85  ac_save_[]FLAGS="$[]FLAGS"
  86 for ac_arg dnl
  87 in "-pedantic -Werror % m4_ifval($1,$1,-option)"  dnl   GCC
  88    "-pedantic % m4_ifval($1,$1,-option) %% no, obsolete"  dnl new GCC
  89    #
  90 do FLAGS="$ac_save_[]FLAGS $[]m4_ifval($2,$2,) "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
  91    AC_TRY_COMPILE([],[return 0;],
  92    [AS_VAR_SET([VAR],[`echo $ac_arg | sed -e 's,.*% *,,'`]) ; break])
  93 done
  94  FLAGS="$ac_save_[]FLAGS"
  95  AC_LANG_RESTORE
  96 ])
  97 AS_VAR_COPY([ac_res], [VAR])
  98 case ".${ac_res}" in
  99      .ok|.ok,*) m4_ifvaln($3,$3) ;;
 100    .|.no|.no,*) m4_ifvaln($4,$4) ;;
 101    *) m4_ifvaln($3,$3,[
 102    if echo " $[]m4_ifval($2,$2,FLAGS) " | grep " ${ac_res} " 2>&1 >/dev/null
 103    then AC_RUN_LOG([: m4_ifval($2,$2,FLAGS) does contain ${ac_res}])
 104    else AC_RUN_LOG([: m4_ifval($2,$2,FLAGS)="$m4_ifval($2,$2,FLAGS) ${ac_res}"])
 105                       m4_ifval($2,$2,FLAGS)="$m4_ifval($2,$2,FLAGS) ${ac_res}"
 106    fi ]) ;;
 107 esac
 108 AS_VAR_POPDEF([VAR])dnl
 109 AS_VAR_POPDEF([FLAGS])dnl
 110 ])