glx: fix shutdown hang
Merge pull request #890 from degasus/glx

glx: fix shutdown hang
Don't sleep in the event thread

The person who wrote this seemed to misunderstand how XPending and
XNextEvent actually work. XNextEvent will wait in poll if there's
no event yet, meaning that we don't need to sleep after we process
all the events; the kernel will sleep for us.

This changes indentation, so view with -w or a similar feature to
understand what's actually changed here.