StdScheduler::Added is not necessarily called from the thread the
procedure is meant to be run on, so introduce yet another StdScheduler
extra method StartOnCurrentThread which on Mac OS X does the actual run
loop registration stuff and needs to be called from the actual thread
the scheduler is supposed to run on

StdSchedulerMac: Remove SCHAdditions objects again
cmake: mac: Reorder compiler flag selection a bit
C4NetIO: Place silly poll timeout fix where it actually helps in case of UDP
cmake: mac: Re-add libs bundling, revert to LegacyFindFreeType for APPLE