Revert "Revert "Fix infloop in GC mark_kboards""

This reverts commit c418c85617babbe7b63730fefb71e2c87a0141af.
This reinstates the original fix, as it had nothing to do
with the behavior reported in bug#33571, which seems to be
the expected behavior.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/keyboard.c b/src/keyboard.c
index 0d56ea3f7ac..dccc6b7f128 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -12011,7 +12011,12 @@ mark_kboards (void)
     for (event = kbd_fetch_ptr; event != kbd_store_ptr; event++)
       {
         if (event == kbd_buffer + KBD_BUFFER_SIZE)
-          event = kbd_buffer;
+          {
+            event = kbd_buffer;
+            if (event == kbd_store_ptr)
+              break;
+          }
+
         /* These two special event types has no Lisp_Objects to mark.  */
         if (event->kind != SELECTION_REQUEST_EVENT
             && event->kind != SELECTION_CLEAR_EVENT)