Work around GCC bug 54561 in a better way

The new approach is less selective, but also less intrusive on C code.
* src/bytecode.c, src/image.c, src/keyboard.c: Ignore -Wclobbered.
* src/conf_post.h (NONVOLATILE): Remove.  All uses removed.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/keyboard.c b/src/keyboard.c
index 653f52732a7..8901ff055e7 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -70,6 +70,11 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include TERM_HEADER
 #endif /* HAVE_WINDOW_SYSTEM */
 
+/* Work around GCC bug 54561.  */
+#if GNUC_PREREQ (4, 3, 0)
+# pragma GCC diagnostic ignored "-Wclobbered"
+#endif
+
 /* Variables for blockinput.h:  */
 
 /* Positive if interrupt input is blocked right now.  */
@@ -2320,7 +2325,7 @@ read_char (int commandflag, Lisp_Object map,
            Lisp_Object prev_event,
            bool *used_mouse_menu, struct timespec *end_time)
 {
-  Lisp_Object NONVOLATILE c;
+  Lisp_Object c;
   ptrdiff_t jmpcount;
   sys_jmp_buf local_getcjmp;
   sys_jmp_buf save_jump;