libvirt/m4/compiler-flags.m4

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# serial 3
# Find valid warning flags for the C Compiler. -*-Autoconf-*-
#
# Copyright (C) 2001, 2002, 2006 Free Software Foundation, Inc.
#
# 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 2 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
# Written by Jesse Thilo.
AC_DEFUN([gl_COMPILER_FLAGS],
[AC_MSG_CHECKING(whether compiler accepts $1)
AC_SUBST(COMPILER_FLAGS)
ac_save_CFLAGS="$CFLAGS"
dnl Some flags are dependant, so we set all previously checked
dnl flags when testing. Except for -Werror which we have to
dnl check on its own, because some of our compiler flags cause
dnl warnings from the autoconf test program!
if test "$1" = "-Werror" ; then
CFLAGS="$CFLAGS $1"
else
CFLAGS="$CFLAGS $COMPILER_FLAGS $1"
fi
AC_TRY_LINK([], [], has_option=yes, has_option=no,)
echo 'int x;' >conftest.c
$CC $CFLAGS -c conftest.c 2>conftest.err
ret=$?
if test $ret != 0 -o -s conftest.err -o $has_option = "no"; then
AC_MSG_RESULT(no)
else
AC_MSG_RESULT(yes)
COMPILER_FLAGS="$COMPILER_FLAGS $1"
fi
CFLAGS="$ac_save_CFLAGS"
rm -f conftest*
])