-# warnings.m4 serial 7
-dnl Copyright (C) 2008-2012 Free Software Foundation, Inc.
+# warnings.m4 serial 8
+dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AS_VAR_PUSHDEF([gl_Flags], [_AC_LANG_PREFIX[]FLAGS])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]), [" $1"])
+ gl_AS_VAR_APPEND(m4_defn([gl_Flags]), [" $gl_unknown_warnings_are_errors $1"])
AC_COMPILE_IFELSE([m4_default([$4], [AC_LANG_PROGRAM([])])],
[AS_VAR_SET(gl_Warn, [yes])],
[AS_VAR_SET(gl_Warn, [no])])
AS_VAR_POPDEF([gl_Warn])dnl
])
+# gl_UNKNOWN_WARNINGS_ARE_ERRORS
+# ------------------------------
+# Clang doesn't complain about unknown warning options unless one also
+# specifies -Wunknown-warning-option -Werror. Detect this.
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS],
+[gl_COMPILER_OPTION_IF([-Werror -Wunknown-warning-option],
+ [gl_unknown_warnings_are_errors='-Wunknown-warning-option -Werror'],
+ [gl_unknown_warnings_are_errors=])])
# gl_WARN_ADD(OPTION, [VARIABLE = WARN_CFLAGS],
# [PROGRAM = AC_LANG_PROGRAM()])
#
# If VARIABLE is a variable name, AC_SUBST it.
AC_DEFUN([gl_WARN_ADD],
-[gl_COMPILER_OPTION_IF([$1],
+[AC_REQUIRE([gl_UNKNOWN_WARNINGS_ARE_ERRORS])
+gl_COMPILER_OPTION_IF([$1],
[gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]), [" $1"])],
[],
[$3])