Or: don’t resume the map until the application has entered the foreground.
UIApplicationWillEnterForegroundNotification is posted before UIApplicationDidBecomeActiveNotification, while the application is still in the background. That caused -createGLView to bail but did not cause the rest of -wakeGL: to bail. We would create the GLKView only after attempting to bind it (a no-op), resulting in a black view.
Fixes#1855.