Remove configure's --without-sync-input option.

When auditing signal-handling in preparation for cleaning it up,
I found that SYNC_INPUT has race conditions and would be a real
pain to fix.  Since it's an undocumented and deprecated
configure-time option, now seems like a good time to remove it.
Also see <http://bugs.gnu.org/11080#16>.
* configure.ac (SYNC_INPUT, BROKEN_SA_RESTART): Remove.
* admin/CPP-DEFINES (BROKEN_SA_RESTART, SA_RESTART): Remove.
* etc/TODO (Make SYNC_INPUT the default): Remove, as the code now
behaves as if SYNC_INPUT is always true.
* src/alloc.c (_bytes_used, __malloc_extra_blocks, _malloc_internal)
(_free_internal) [!DOUG_LEA_MALLOC]: Remove decls.
(alloc_mutex) [!SYSTEM_MALLOC && !SYNC_INPUT && HAVE_PTHREAD]:
(malloc_hysteresis):
(check_depth) [XMALLOC_OVERRUN_CHECK]:
(MALLOC_BLOCK_INPUT, MALLOC_UNBLOCK_INPUT):
(__malloc_hook, __realloc_hook, __free_hook, BYTES_USED)
(dont_register_blocks, bytes_used_when_reconsidered)
(bytes_used_when_full, emacs_blocked_free, emacs_blocked_malloc)
(emacs_blocked_realloc, reset_malloc_hooks, uninterrupt_malloc):
[!SYSTEM_MALLOC && !SYNC_INPUT]:
Remove. All uses removed.
(MALLOC_BLOCK_INPUT, MALLOC_UNBLOCK_INPUT): Use a different
implementation, one that depends on whether the new macro
XMALLOC_BLOCK_INPUT_CHECK is defined, not on whether SYNC_INPUT
is defined.
* src/atimer.c (run_timers, handle_alarm_signal):
* src/keyboard.c (pending_signal, poll_for_input_1, poll_for_input)
(handle_async_input, process_pending_signals)
(handle_input_available_signal, init_keyboard):
* src/nsterm.m (ns_read_socket):
* src/process.c (wait_reading_process_output):
* src/regex.c (immediate_quit, IMMEDIATE_QUIT_CHECK):
* src/sysdep.c (emacs_sigaction_init) [SA_RESTART]:
(emacs_write):
* src/xterm.c (XTread_socket):
Assume SYNC_INPUT.
* src/conf_post.h (SA_RESTART) [IRIX6_5]: Do not #undef.
* src/eval.c (handling_signal): Remove.  All uses removed.
* src/lisp.h (ELSE_PENDING_SIGNALS): Remove.
All uses replaced with the SYNC_INPUT version.
(reset_malloc_hooks, uninterrupt_malloc, handling_signal):
Remove decls.
* src/sysdep.c, src/syssignal.h (main_thread) [FORWARD_SIGNAL_TO_MAIN_THREAD]:
Now static.

Fixes: debbugs:12450

1 files changed, 2 insertions, 11 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 447c6bd296b..3a473a60b48 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2107,22 +2107,16 @@ extern char *stack_bottom;
    If quit-flag is set to `kill-emacs' the SIGINT handler has received
    a request to exit Emacs when it is safe to do.  */
 
-#ifdef SYNC_INPUT
 extern void process_pending_signals (void);
 extern int pending_signals;
-#define ELSE_PENDING_SIGNALS				\
-  else if (pending_signals)				\
-    process_pending_signals ();
-#else  /* not SYNC_INPUT */
-#define ELSE_PENDING_SIGNALS
-#endif	/* not SYNC_INPUT */
 
 extern void process_quit_flag (void);
 #define QUIT						\
   do {							\
     if (!NILP (Vquit_flag) && NILP (Vinhibit_quit))	\
       process_quit_flag ();				\
-    ELSE_PENDING_SIGNALS				\
+    else if (pending_signals)				\
+      process_pending_signals ();			\
   } while (0)
 
 
@@ -2846,8 +2840,6 @@ extern void memory_warnings (void *, void (*warnfun) (const char *));
 /* Defined in alloc.c.  */
 extern void check_pure_size (void);
 extern void allocate_string_data (struct Lisp_String *, EMACS_INT, EMACS_INT);
-extern void reset_malloc_hooks (void);
-extern void uninterrupt_malloc (void);
 extern void malloc_warning (const char *);
 extern _Noreturn void memory_full (size_t);
 extern _Noreturn void buffer_memory_full (ptrdiff_t);
@@ -3043,7 +3035,6 @@ extern Lisp_Object Qand_rest;
 extern Lisp_Object Vautoload_queue;
 extern Lisp_Object Vsignaling_function;
 extern Lisp_Object inhibit_lisp_code;
-extern int handling_signal;
 #if BYTE_MARK_STACK
 extern struct catchtag *catchlist;
 extern struct handler *handlerlist;