add rtgui_event_timer_t define

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1809 bbd45198-f89e-11dd-88c7-29a3b14d5316

components/rtgui/include/rtgui/event.h

@@ -285,6 +285,8 @@ struct rtgui_event_timer
 
 	struct rtgui_timer *timer;
 };
+typedef struct rtgui_event_timer rtgui_event_timer_t;
+
 
 struct rtgui_event_clip_info
 {