dnl $Id$

dnl * Check if the compiler understands a certain flag or not.
dnl   Inspiration for this came from watching TagLib configure.
dnl * Check for the CFLAG required to turn warnings into errors.

dnl Copyright (c) 2008 Moritz Grimm <mgrimm@mrsserver.net>
dnl
dnl Permission to use, copy, modify, and distribute this software for any
dnl purpose with or without fee is hereby granted, provided that the above
dnl copyright notice and this permission notice appear in all copies.
dnl
dnl THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
dnl WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
dnl MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
dnl ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
dnl WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
dnl ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
dnl OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

dnl AX_CHECK_CFLAG(CFLAG, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
dnl AX_CHECK_CXXFLAG(CXXFLAG, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])

AC_DEFUN([AX_CHECK_CFLAG],
[
AC_MSG_CHECKING([if ${CC} understands -$1])
_cv_sufx_=$(echo $1 | sed 'y|-+,= |_p___|')
AC_CACHE_VAL([local_cv_prog_cc_${_cv_sufx_}],
[
	AC_LANG_PUSH([C])
	save_CFLAGS="${CFLAGS}"
	CFLAGS="${CFLAGS} -$1"
	AC_TRY_LINK([], [],
		[eval "local_cv_prog_cc_${_cv_sufx_}=yes"],
		[eval "local_cv_prog_cc_${_cv_sufx_}=no"])
	CFLAGS="${save_CFLAGS}"
	AC_LANG_POP([C])
])
eval "_cache_val_=\${local_cv_prog_cc_${_cv_sufx_}}"
if test x"${_cache_val_}" = "xyes"; then
	AC_MSG_RESULT([yes])
	:
	$2
else
	AC_MSG_RESULT([no])
	:
	$3
fi
])

AC_DEFUN([AX_CHECK_CXXFLAG],
[
AC_MSG_CHECKING([if ${CXX} understands -$1])
_cv_sufx_=$(echo $1 | sed 'y|-+,= |_p___|')
AC_CACHE_VAL([local_cv_prog_cxx_${_cv_sufx_}],
[
	AC_LANG_PUSH([C++])
	save_CXXFLAGS="${CXXFLAGS}"
	CXXFLAGS="${CXXFLAGS} -$1"
	AC_TRY_LINK([], [],
		[eval "local_cv_prog_cxx_${_cv_sufx_}=yes"],
		[eval "local_cv_prog_cxx_${_cv_sufx_}=no"])
	CXXFLAGS="${save_CXXFLAGS}"
	AC_LANG_POP([C++])
])
eval "_cache_val_=\${local_cv_prog_cxx_${_cv_sufx_}}"
if test x"${_cache_val_}" = "xyes"; then
	AC_MSG_RESULT([yes])
	:
	$2
else
	AC_MSG_RESULT([no])
	:
	$3
fi
])

AC_DEFUN([AX_CHECK_ERROR_FLAG],
[
AC_CACHE_VAL([local_cv_prog_cc_error_flag],
[
	AC_MSG_CHECKING([if ${CC} supports an error flag])
	AC_LANG_PUSH([C])
	save_CFLAGS="${CFLAGS}"
	CFLAGS="${CFLAGS} -Werror"
	AC_TRY_LINK([], [],
		[local_cv_prog_cc_error_flag=-Werror],
		[local_cv_prog_cc_error_flag=no])
	CFLAGS="${save_CFLAGS}"
	AC_LANG_POP([C])
	if test x"${local_cv_prog_cc_error_flag}" != "xno"; then
		AC_MSG_RESULT([yes (${local_cv_prog_cc_error_flag})])
		:
		$2
	else
		AC_MSG_RESULT([no])
		:
		$3
	fi
])
])