-# warnings.m4 serial 2
-dnl Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
+# warnings.m4 serial 13
+dnl Copyright (C) 2008-2018 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.
[m4_define([gl_AS_VAR_APPEND],
[AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])])
-# 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],
-[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_$1])dnl
-AC_CACHE_CHECK([whether compiler handles $1], [gl_Warn], [
- save_CPPFLAGS="$CPPFLAGS"
- CPPFLAGS="${CPPFLAGS} $1"
- AC_PREPROC_IFELSE([AC_LANG_PROGRAM([])],
- [AS_VAR_SET([gl_Warn], [yes])],
- [AS_VAR_SET([gl_Warn], [no])])
- CPPFLAGS="$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.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_COMPILER_OPTION_IF],
+[
+dnl FIXME: gl_Warn must be used unquoted until we can assume Autoconf
+dnl 2.64 or newer.
+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"
])
-AS_VAR_PUSHDEF([gl_Flags], m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]))dnl
-AS_VAR_IF([gl_Warn], [yes], [gl_AS_VAR_APPEND([gl_Flags], [" $1"])])
+AS_VAR_IF(gl_Warn, [yes], [$2], [$3])
+m4_popdef([gl_Positive])dnl
AS_VAR_POPDEF([gl_Flags])dnl
AS_VAR_POPDEF([gl_Warn])dnl
-m4_ifval([$2], [AS_LITERAL_IF([$2], [AC_SUBST([$2])], [])])dnl
])
+
+# gl_UNKNOWN_WARNINGS_ARE_ERRORS
+# ------------------------------
+# Clang doesn't complain about unknown warning options unless one also
+# specifies -Wunknown-warning-option -Werror. Detect this.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS],
+[_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
+
+# Specialization for _AC_LANG = C. This macro can be AC_REQUIREd.
+# Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
+m4_defun([gl_UNKNOWN_WARNINGS_ARE_ERRORS(C)],
+[
+ AC_LANG_PUSH([C])
+ gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL
+ AC_LANG_POP([C])
+])
+
+# Specialization for _AC_LANG = C++. This macro can be AC_REQUIREd.
+# Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
+m4_defun([gl_UNKNOWN_WARNINGS_ARE_ERRORS(C++)],
+[
+ AC_LANG_PUSH([C++])
+ gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL
+ AC_LANG_POP([C++])
+])
+
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL],
+[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/WARN_CXXFLAGS],
+# [PROGRAM = AC_LANG_PROGRAM()])
+# -----------------------------------------------------------
+# Adds parameter to WARN_CFLAGS/WARN_CXXFLAGS if the compiler supports it
+# when compiling PROGRAM. For example, gl_WARN_ADD([-Wparentheses]).
+#
+# If VARIABLE is a variable name, AC_SUBST it.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_WARN_ADD],
+[AC_REQUIRE([gl_UNKNOWN_WARNINGS_ARE_ERRORS(]_AC_LANG[)])
+gl_COMPILER_OPTION_IF([$1],
+ [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_]_AC_LANG_PREFIX[FLAGS]], [[$2]]), [" $1"])],
+ [],
+ [$3])
+m4_ifval([$2],
+ [AS_LITERAL_IF([$2], [AC_SUBST([$2])])],
+ [AC_SUBST([WARN_]_AC_LANG_PREFIX[FLAGS])])dnl
+])
+
+# Local Variables:
+# mode: autoconf
+# End: