Replace #pragma mark -'s with named pragmas.
Remove sysctl wrapper, not used on Linux.
Simplify thread functor invocation to remove NFunctorInvoker.
Added NThreadUtilities::MemoryBarrier.
Re-order AtomicOr32/AtomicXor32 to match declarations.
Use intrinsic form of InterlockedCompareExchange/ExchangeAdd.
Use OSSpinLock API for NSpinLock on Mac.
Implement NMutexLock as Benaphore for Mac.