退出程序时清理主循环

src/main.c

@@ -903,6 +903,9 @@ gboolean handle_xcb_event(GIOChannel *channel, GIOCondition condition,
 }
 
 void cleanup(void) {
+  g_main_loop_unref(loop);
+  loop = NULL;
+
   monitor_t *m = monitors;
   client_t *c = m->clients;
   while (m) {