btrfs-progs/m4/ax_check_define.m4

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# ===========================================================================
# http://www.gnu.org/software/autoconf-archive/ax_check_define.html
# ===========================================================================
#
# SYNOPSIS
#
# AC_CHECK_DEFINE([symbol], [ACTION-IF-FOUND], [ACTION-IF-NOT])
# AX_CHECK_DEFINE([includes],[symbol], [ACTION-IF-FOUND], [ACTION-IF-NOT])
#
# DESCRIPTION
#
# Complements AC_CHECK_FUNC but it does not check for a function but for a
# define to exist. Consider a usage like:
#
# AC_CHECK_DEFINE(__STRICT_ANSI__, CFLAGS="$CFLAGS -D_XOPEN_SOURCE=500")
#
# LICENSE
#
# Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 3 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
#
# As a special exception, the respective Autoconf Macro's copyright owner
# gives unlimited permission to copy, distribute and modify the configure
# scripts that are the output of Autoconf when processing the Macro. You
# need not follow the terms of the GNU General Public License when using
# or distributing such scripts, even though portions of the text of the
# Macro appear in them. The GNU General Public License (GPL) does govern
# all other use of the material that constitutes the Autoconf Macro.
#
# This special exception to the GPL applies to versions of the Autoconf
# Macro released by the Autoconf Archive. When you make and distribute a
# modified version of the Autoconf Macro, you may extend this special
# exception to the GPL to apply to your modified version as well.
#serial 8
AU_ALIAS([AC_CHECK_DEFINED], [AC_CHECK_DEFINE])
AC_DEFUN([AC_CHECK_DEFINE],[
AS_VAR_PUSHDEF([ac_var],[ac_cv_defined_$1])dnl
AC_CACHE_CHECK([for $1 defined], ac_var,
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[
#ifdef $1
int ok;
#else
choke me
#endif
]])],[AS_VAR_SET(ac_var, yes)],[AS_VAR_SET(ac_var, no)]))
AS_IF([test AS_VAR_GET(ac_var) != "no"], [$2], [$3])dnl
AS_VAR_POPDEF([ac_var])dnl
])
AU_ALIAS([AX_CHECK_DEFINED], [AX_CHECK_DEFINE])
AC_DEFUN([AX_CHECK_DEFINE],[
AS_VAR_PUSHDEF([ac_var],[ac_cv_defined_$2_$1])dnl
AC_CACHE_CHECK([for $2 defined in $1], ac_var,
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <$1>]], [[
#ifdef $2
int ok;
#else
choke me
#endif
]])],[AS_VAR_SET(ac_var, yes)],[AS_VAR_SET(ac_var, no)]))
AS_IF([test AS_VAR_GET(ac_var) != "no"], [$3], [$4])dnl
AS_VAR_POPDEF([ac_var])dnl
])
AC_DEFUN([AX_CHECK_FUNC],
[AS_VAR_PUSHDEF([ac_var], [ac_cv_func_$2])dnl
AC_CACHE_CHECK([for $2], ac_var,
dnl AC_LANG_FUNC_LINK_TRY
[AC_LINK_IFELSE([AC_LANG_PROGRAM([$1
#undef $2
char $2 ();],[
char (*f) () = $2;
return f != $2; ])],
[AS_VAR_SET(ac_var, yes)],
[AS_VAR_SET(ac_var, no)])])
AS_IF([test AS_VAR_GET(ac_var) = yes], [$3], [$4])dnl
AS_VAR_POPDEF([ac_var])dnl
])# AC_CHECK_FUNC