emacs-30 9e7c2d3816e: Avoid rare crashes due to clobbering of input events

[Eli Zaretskii]

branch: emacs-30
commit 9e7c2d3816ec3e1247b1bd3cfcafc60a84b0f5ec
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Avoid rare crashes due to clobbering of input events
    
    * src/keyboard.c (read_char): Declare C 'volatile', to prevent
    clobbering it by setjmp/longjmp.  Do not merge to master.
    (Bug#71744)
---
 src/keyboard.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/keyboard.c b/src/keyboard.c
index c75e80d2a05..e7b0af9f63c 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -2522,7 +2522,7 @@ read_char (int commandflag, Lisp_Object map,
           Lisp_Object prev_event,
           bool *used_mouse_menu, struct timespec *end_time)
 {
-  Lisp_Object c;
+  volatile Lisp_Object c;
   sys_jmp_buf local_getcjmp;
   sys_jmp_buf save_jump;
   Lisp_Object tem, save;