Mac: Fixed crash when returning from a fullscreen Space on shutdown.

src/video/cocoa/SDL_cocoakeyboard.m

@@ -565,6 +565,10 @@ void
 Cocoa_HandleKeyEvent(_THIS, NSEvent *event)
 {
     SDL_VideoData *data = (SDL_VideoData *) _this->driverdata;
+    if (!data) {
+        return;  /* can happen when returning from fullscreen Space on shutdown */
+    }
+
     unsigned short scancode = [event keyCode];
     SDL_Scancode code;
 #if 0

src/video/cocoa/SDL_cocoamouse.m

@@ -349,8 +349,11 @@ Cocoa_HandleMouseEvent(_THIS, NSEvent *event)
     }
 
     SDL_Mouse *mouse = SDL_GetMouse();
-
     SDL_MouseData *driverdata = (SDL_MouseData*)mouse->driverdata;
+    if (!driverdata) {
+        return;  /* can happen when returning from fullscreen Space on shutdown */
+    }
+
     const SDL_bool seenWarp = driverdata->seenWarp;
     driverdata->seenWarp = NO;