From 51a2f83b28d1e6164e0b7f2fddd5243f3137fd91 Mon Sep 17 00:00:00 2001
From: raveit65 <mate@raveit.de>
Date: Fri, 27 Sep 2019 14:32:25 +0200
Subject: Revert "update mate-compiler-flags macro"

This reverts commit ad0857b239facbfe89199923c15988aacb00806e.

Better not for 1.22
---
 macros/mate-compiler-flags.m4 | 71 ++++++++++++++++++++++++++++++-------------
 1 file changed, 50 insertions(+), 21 deletions(-)

diff --git a/macros/mate-compiler-flags.m4 b/macros/mate-compiler-flags.m4
index 6ba33be..4b5ecc0 100644
--- a/macros/mate-compiler-flags.m4
+++ b/macros/mate-compiler-flags.m4
@@ -28,7 +28,13 @@ AC_DEFUN([MATE_COMPILE_WARNINGS],[
                                  [Turn on compiler warnings]),,
                   [enable_compile_warnings="m4_default([$1],[yes])"])
 
-    AC_LANG_PUSH([C])
+    warnCFLAGS=
+    if test "x$GCC" != xyes; then
+	enable_compile_warnings=no
+    fi
+
+    warning_flags=
+    realsave_CFLAGS="$CFLAGS"
 
     case "$enable_compile_warnings" in
     no)
@@ -41,7 +47,24 @@ AC_DEFUN([MATE_COMPILE_WARNINGS],[
 	warning_flags="-Wall -Wmissing-prototypes"
 	;;
     maximum|error)
-	warning_flags="-Wall -Wmissing-prototypes -Wbad-function-cast -Wcast-align -Wextra -Wformat-nonliteral -Wmissing-declarations -Wmissing-field-initializers -Wnested-externs -Wpointer-arith -Wredundant-decls -Wshadow -Wstrict-prototypes -Werror=format-security -Wno-sign-compare"
+	warning_flags="-Wall -Wmissing-prototypes -Wnested-externs -Wpointer-arith"
+	CFLAGS="$warning_flags $CFLAGS"
+	for option in -Wno-sign-compare; do
+		SAVE_CFLAGS="$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="$warning_flags -Werror"
 	fi
@@ -50,26 +73,32 @@ AC_DEFUN([MATE_COMPILE_WARNINGS],[
 	AC_MSG_ERROR(Unknown argument '$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)
+
+    AC_ARG_ENABLE(iso-c,
+                  AS_HELP_STRING([--enable-iso-c],
+                                 [Try to warn if code is not ISO C ]),,
+                  [enable_iso_c=no])
+
+    AC_MSG_CHECKING(what language compliance flags to pass to the C compiler)
+    complCFLAGS=
+    if test "x$enable_iso_c" != "xno"; then
+	if test "x$GCC" = "xyes"; then
+	case " $CFLAGS " in
+	    *[\ \	]-ansi[\ \	]*) ;;
+	    *) complCFLAGS="$complCFLAGS -ansi" ;;
+	esac
+	case " $CFLAGS " in
+	    *[\ \	]-pedantic[\ \	]*) ;;
+	    *) complCFLAGS="$complCFLAGS -pedantic" ;;
+	esac
+	fi
+    fi
+    AC_MSG_RESULT($complCFLAGS)
 
-    # Always pass -Werror=unknown-warning-option to get Clang to fail on bad
-    # flags, otherwise they are always appended to the warn_cflags variable, and
-    # Clang warns on them for every compilation unit.
-    # If this is passed to GCC, it will explode, so the flag must be enabled
-    # conditionally.
-    AX_CHECK_COMPILE_FLAG([-Werror=unknown-warning-option],[
-        compiler_flags_test="-Werror=unknown-warning-option"
-    ],[
-        compiler_flags_test=""
-    ])
-
-    for flag in $warning_flags; do
-         AX_CHECK_COMPILE_FLAG([$flag], [AX_APPEND_FLAG([$flag], [WARN_CFLAGS])], [], [$compiler_flags_test], [])
-    done
-
-    AC_MSG_CHECKING(flags to pass to the C compiler $CC)
-    AC_MSG_RESULT(${WARN_CFLAGS})
-
-    AC_LANG_POP([C])
+    WARN_CFLAGS="$warning_flags $complCFLAGS"
     AC_SUBST(WARN_CFLAGS)
 ])
 
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