-# gl_WARN_ADD(PARAMETER, [VARIABLE = WARN_CFLAGS])
-# ------------------------------------------------
-# Adds parameter to WARN_CFLAGS if the compiler supports it. For example,
-# gl_WARN_ADD([-Wparentheses]).
-AC_DEFUN([gl_WARN_ADD],
-dnl FIXME: gl_Warn must be used unquoted until we can assume
-dnl autoconf 2.64 or newer.
-[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_$1])dnl
-AC_CACHE_CHECK([whether compiler handles $1], m4_defn([gl_Warn]), [
- gl_save_CPPFLAGS="$CPPFLAGS"
- CPPFLAGS="${CPPFLAGS} $1"
- AC_PREPROC_IFELSE([AC_LANG_PROGRAM([])],
- [AS_VAR_SET(gl_Warn, [yes])],
- [AS_VAR_SET(gl_Warn, [no])])
- CPPFLAGS="$gl_save_CPPFLAGS"
+
+# gl_COMPILER_OPTION_IF(OPTION, [IF-SUPPORTED], [IF-NOT-SUPPORTED],
+# [PROGRAM = AC_LANG_PROGRAM()])
+# -----------------------------------------------------------------
+# Check if the compiler supports OPTION when compiling PROGRAM.
+#
+# FIXME: gl_Warn must be used unquoted until we can assume Autoconf
+# 2.64 or newer.
+AC_DEFUN([gl_COMPILER_OPTION_IF],
+[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_[]_AC_LANG_ABBREV[]_$1])dnl
+AS_VAR_PUSHDEF([gl_Flags], [_AC_LANG_PREFIX[]FLAGS])dnl
+AS_LITERAL_IF([$1],
+ [m4_pushdef([gl_Positive], m4_bpatsubst([$1], [^-Wno-], [-W]))],
+ [gl_positive="$1"
+case $gl_positive in
+ -Wno-*) gl_positive=-W`expr "X$gl_positive" : 'X-Wno-\(.*\)'` ;;
+esac
+m4_pushdef([gl_Positive], [$gl_positive])])dnl
+AC_CACHE_CHECK([whether _AC_LANG compiler handles $1], m4_defn([gl_Warn]), [
+ gl_save_compiler_FLAGS="$gl_Flags"
+ gl_AS_VAR_APPEND(m4_defn([gl_Flags]),
+ [" $gl_unknown_warnings_are_errors ]m4_defn([gl_Positive])["])
+ AC_LINK_IFELSE([m4_default([$4], [AC_LANG_PROGRAM([])])],
+ [AS_VAR_SET(gl_Warn, [yes])],
+ [AS_VAR_SET(gl_Warn, [no])])
+ gl_Flags="$gl_save_compiler_FLAGS"