diff --git a/src/keyboard.h b/src/keyboard.h
index 08cb934d3fe..8df3a2452a7 100644
--- a/src/keyboard.h
+++ b/src/keyboard.h
@@ -330,6 +330,7 @@ extern int lucid_event_type_list_p P_ ((Lisp_Object));
 extern void kbd_buffer_store_event P_ ((struct input_event *));
 extern void kbd_buffer_store_event_hold P_ ((struct input_event *,
 					     struct input_event *));
+extern void kbd_buffer_unget_event P_ ((struct input_event *));
 #ifdef POLL_FOR_INPUT
 extern void poll_for_input_1 P_ ((void));
 #endif