Fixed Mac and Linux builds
diff --git a/src/dynapi/SDL_dynapi_procs.h b/src/dynapi/SDL_dynapi_procs.h
index e25bbda..ce31a59 100644
--- a/src/dynapi/SDL_dynapi_procs.h
+++ b/src/dynapi/SDL_dynapi_procs.h
@@ -624,4 +624,6 @@ SDL_DYNAPI_PROC(int,SDL_QueueAudio,(SDL_AudioDeviceID a, const void *b, Uint32 c
SDL_DYNAPI_PROC(Uint32,SDL_GetQueuedAudioSize,(SDL_AudioDeviceID a),(a),return)
SDL_DYNAPI_PROC(void,SDL_ClearQueuedAudio,(SDL_AudioDeviceID a),(a),)
SDL_DYNAPI_PROC(SDL_Window*,SDL_GetGrabbedWindow,(void),(),return)
+#ifdef __WIN32__
SDL_DYNAPI_PROC(void,SDL_SetWindowsMessageHook,(SDL_WindowsMessageHook a),(a),)
+#endif