On Linux, just call the tick callback on every loop tick. This is much
simpler, and should fix the issue with screen updates sometimes getting
stuck waiting for an X11 event.
Note that this was what used to happen (global state being checked on
every loop tick) before the refactoring to use a GLFW event loop,
therefore there should be no performance regressions, though we
of course end up checking global state on every group of events on
Linux, instead of only when something of interest happens. I suspect, to
achieve the latter is going to require implementing a mutex/lock in the
main loop to avoid races, which doesn't seem worth it.
This should make tracking down the root cause of the
event loop pauses on X11 easier. And the infrastructure
should come in handy in the future as well.
