-extern void buz_init(void);
-extern void buz_beep(mtime_t time);
-extern void buz_repeat_start(mtime_t duration, mtime_t interval);
-extern void buz_repeat_stop(void);
+void buz_init(void);
+void buz_beep(mtime_t time);
+void buz_repeat_start(mtime_t duration, mtime_t interval);
+void buz_repeat_stop(void);