[PR89221] Continue to default to '--disable-frame-pointer' for x86 GNU systems

The recent trunk r270914 for PR89221 "--enable-frame-pointer does not work as
intended" fixed a scripting defect in the x86 '--enable-frame-pointer'
handling.

This has the side effect that, for example, for '--target=i686-gnu' this is now
enabled by default: 'USE_IX86_FRAME_POINTER=1' is added to 'tm_defines'.  Given
that it's highly unlikely that anyone would now suddenly want
'--enable-frame-pointer' as the default for any kind of GNU system, I'm
changing the default back for GNU systems, to match that of a 'target_os' of
'linux* | darwin[8912]*'.

	gcc/
	PR target/89221
	* configure.ac (--enable-frame-pointer): Disable by default for
	GNU systems.
	* configure: Regenerate.

From-SVN: r271028

gcc/ChangeLog

+2019-05-09  Thomas Schwinge  <thomas@codesourcery.com>
+
+	PR target/89221
+	* configure.ac (--enable-frame-pointer): Disable by default for
+	GNU systems.
+	* configure: Regenerate.
+
 2019-05-09  Alan Modra  <amodra@gmail.com>
 
 	PR target/89271

gcc/configure

@@ -12197,8 +12197,8 @@ if test "${enable_frame_pointer+set}" = set; then :
 else
 
 case $target_os in
-linux* | darwin[8912]*)
-  # Enable -fomit-frame-pointer by default for Linux and Darwin with DWARF2.
+linux* | gnu* | darwin[8912]*)
+  # Enable -fomit-frame-pointer by default for these systems with DWARF2.
   enable_frame_pointer=no
   ;;
 *)

gcc/configure.ac

@@ -1884,8 +1884,8 @@ AC_ARG_ENABLE(frame-pointer,
 		[enable -fno-omit-frame-pointer by default for x86])], [],
 [
 case $target_os in
-linux* | darwin[[8912]]*)
-  # Enable -fomit-frame-pointer by default for Linux and Darwin with DWARF2.
+linux* | gnu* | darwin[[8912]]*)
+  # Enable -fomit-frame-pointer by default for these systems with DWARF2.
   enable_frame_pointer=no
   ;;
 *)