Added native atomic operations for Windows, Mac OS X, and gcc compiler intrinsics. Changed the CAS return value to bool, so it's efficient with OSAtomicCompareAndSwap32Barrier() Added an atomic test adapted from code by Michael Davidsaver

The test programs in this directory tree are for demonstrating and
testing the functionality of the SDL library, and are placed in the
public domain.

October 28, 1997
--
	Sam Lantinga				(slouken@libsdl.org)