# $Id$

# if the given code compiles without the flag, execute argument 4
# if the given code only compiles with the flag, execute argument 3
# otherwise fail
AC_DEFUN([CHECK_COMPILER_FLAG_NEEDED],[
	AC_REQUIRE([AC_PROG_CC])
	AC_MSG_CHECKING(whether we need $1 as a flag for $CC)
	cache=`echo $1 | sed 'y% .=/+-%____p_%'`
	AC_CACHE_VAL(cv_prog_cc_flag_needed_$cache,
	[
		echo '$2' > conftest.c
		echo 'void f(){}' >>conftest.c
		if test -z "`$CC $CFLAGS -Werror -Wall -c conftest.c 2>&1`"; then
			eval "cv_prog_cc_flag_needed_$cache=no"
		else
		[
			if test -z "`$CC $CFLAGS $1 -Werror -Wall -c conftest.c 2>&1`"; then
				eval "cv_prog_cc_flag_needed_$cache=yes"
			else
				echo 'Test with flag fails too'
			fi
		]
		fi
		rm -f conftest*
	])
	if eval "test \"`echo '$cv_prog_cc_flag_needed_'$cache`\" = yes"; then
		AC_MSG_RESULT(yes)
		:
		$3
	else
		AC_MSG_RESULT(no)
		:
		$4
	fi
])