Make note to send it, and send next time we SDL_PumpEvents().
Otherwise, we might be trying to use malloc() to push a new event on the
queue while a signal is interrupting malloc() elsewhere, usually causing a
crash.
Fixes Bugzilla #2870.
An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.
Fixes Bugzilla #2944.
