程序结束时清理 xcb 模块环境

src/include/xcb.h

@@ -22,3 +22,4 @@ typedef struct window_list_t {
 } window_list_t;
 window_list_t *scan_window_list(void);
 void free_window_list(window_list_t *window_list);
+void clean_xcb(void);