This solves a problem where sometimes FEX would spin up a new process
while FEXMountDaemon was in the process of shutting down. Breaking
things on both sides.
Now the race conditions are squashed that I could see.
Also fixes one race where FEX is starting up and FEXMountDaemon is
spinning up. This case is where FEX managed to pull the lock file just
before it got deleted. Then sent the FEXMountDaemon a request to be
observed. With DGRAM sockets we would fire and forget. Use a STREAM with
a ack result so we know we can return.
This isn't quite a 100% clean sweep of IWYU.
There are some false positives where clang fails.
Additionally there are still a few missed in the frontend side of things
that I didn't get to
Puts the visibility of the main layer, application layers, and
environment in to FEXCore instead of FEX.
These layers aren't specific to FEX/FEXLoader and should live in
FEXCore.
Only the EmptyMapper remains in FEX, which should eventually move over
to FEXConfig since that is the only user.
Ryan Houdek