OSX: Disable synthetic touch=>mouse conversion

No idea if this will help with QW-Group#354, need
  someone with touchbar to test
(or someone to explain to me how to use touchbar
  simulator in xcode with ezQuake)

vid_sdl2.c

@@ -1367,6 +1367,11 @@ static void VID_SDL_Init(void)
 #endif
 	SDL_SetHint(SDL_HINT_GRAB_KEYBOARD, vid_grab_keyboard.integer == 0 ? "0" : "1");
 	SDL_SetHintWithPriority(SDL_HINT_MOUSE_RELATIVE_MODE_WARP, "0", SDL_HINT_OVERRIDE);
+#ifdef __APPLE__
+#ifdef SDL_HINT_TOUCH_MOUSE_EVENTS
+	SDL_SetHint(SDL_HINT_TOUCH_MOUSE_EVENTS, "0");
+#endif
+#endif
 
 	{
 		int i;