add proto

src/include/switch_core.h

@@ -139,6 +139,7 @@ struct switch_core_port_allocator;
 ///\{
 
 
+SWITCH_DECLARE(void) switch_core_screen_size(int *x, int *y);
 SWITCH_DECLARE(void) switch_core_session_sched_heartbeat(switch_core_session_t *session, uint32_t seconds);
 SWITCH_DECLARE(void) switch_core_session_unsched_heartbeat(switch_core_session_t *session);