instead of calling CFRunLoopRun() directly. The leak wasn't reproducible on
this machine, but someone was able to produce a leak trace with Instruments
that indicates it was leaking in the CFRunLoopRun() path.
x-input.m: dequeue and ignore events when pbproxy_active is false.
x-selection.h: add an is_active method that is used by x-input.m to ignore
events.
x-selection.m: Handle nearly every preference, except for primary_on_grab,
which I don't really understand yet.
(cherry picked from commit 4d51ad851e64da83cbdfb0a4a22428418a7bcf75)
7bb73a9513