The semaphore emulation lib provides for sem_timedwait() which will allow
correct blocking calls to be used rather than bogus (On *nix anyways)
arbitrary 1-55ms (depending on hardware) wait during a loop to avoid 100%
CPU utilization.

The xpsem lib uses mutexes to provide semaphore functions and is taken
almost line-per-line from FreeBSD.  (copyright left intact)

**** WARNING ****
This commit was performed while drunk.  If this breaks your build, I
personally guarantee you get to keep all remaning pieces.