dnl Turn on the additional warnings last, so -Werror doesn't affect other tests.

AC_DEFUN([LM_COMPILE_WARNINGS],[

   if test -f $srcdir/autogen.sh; then

	default_compile_warnings="error"

    else

	default_compile_warnings="no"

    fi

    AC_ARG_WITH(compile-warnings, [  --with-compile-warnings=[no/yes/error] Compiler warnings ], [enable_compile_warnings="$withval"], [enable_compile_warnings="$default_compile_warnings"])

    warnCFLAGS=

    if test "x$GCC" != xyes; then

	enable_compile_warnings=no

    fi

    warning_flags=

    realsave_CFLAGS="$CFLAGS"

    case "$enable_compile_warnings" in

    no)

	warning_flags=

	;;

    yes)

	warning_flags="-Wall -Wunused -Wmissing-prototypes -Wmissing-declarations"

	;;

    maximum|error)

	warning_flags="-Wall -Wunused -Wchar-subscripts -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wpointer-arith"

	CFLAGS="$warning_flags $CFLAGS"

	for option in -Wsign-promo -Wno-sign-compare; do

		SAVE_CFLAGS="$CFLAGS"

		CFLAGS="$CFLAGS $option"

		AC_MSG_CHECKING([whether gcc understands $option])

		AC_TRY_COMPILE([], [],

			has_option=yes,

			has_option=no,)

		CFLAGS="$SAVE_CFLAGS"

		AC_MSG_RESULT($has_option)

		if test $has_option = yes; then

		  warning_flags="$warning_flags $option"

		fi

		unset has_option

		unset SAVE_CFLAGS

	done

	unset option

	if test "$enable_compile_warnings" = "error" ; then

	    warning_flags="$warning_flags -Werror"

	fi

	;;

    *)

	AC_MSG_ERROR(Unknown argument '$enable_compile_warnings' to --enable-compile-warnings)

	;;

    esac

    CFLAGS="$realsave_CFLAGS"

    AC_MSG_CHECKING(what warning flags to pass to the C compiler)

    AC_MSG_RESULT($warning_flags)

    WARN_CFLAGS="$warning_flags"

    AC_SUBST(WARN_CFLAGS)

])