I've made so many changes I don't dare continue until I check the current stuff in. /test/testatomic.c performs absolutely basic tests to show that the function work as expected. Need a second test to do more detailed tests. /include/SDL_atomic.h provides declarations for all included functions. /src/atomic/linux/SDL_atomic.c provided all the functions. On a generic built the 64 bit functions work, but they are emulated. On a build for -march=pentium and above the 64 bit functions use native instructions /src/atomic/dummy/SDL_atomic.c emulates all the operations using SDL_mutex.h. /src/atomic/win32/SDL_atomic.c is a copy of dummy /src/atomic/macosx/SDL_atomic.s is a copy of dummy These versions of SDL_atomic.c provide a frame work for building the library with a mixture of native and emulated functions. This allows the whole library to be provided on all platforms. (I hope.) I hope this fits with the SDL philosophy of either providing a common subset or emulating when the platform is missing a feature. I have not added dummy, macosx, or win32 to the build. They are there as place holders for future work. I have modified congifure.in to compile sources in /src/atomic/linux. (The SDL configure.in file is an amazing piece of work and I hope I didn't mess it up. :-)

TestiPhoneOS.xcodeproj contains targets to compile many of the SDL test programs for iPhone OS.  Most of these test programs work fine, with the following exceptions:

testalpha:
	Program crashes.  Problem appears to effect Mac OS X as well.

testhread:
	SIGTERM kills the process immediately without executing the 'kill' function.  The posix standard says this shouldn't happen.  Apple seems intent on having iPhone apps exit promptly when the user requests it, so maybe that's why(?)

testlock:
	Locks appear to work, but there doesn't appear to be a simple way to send the process SIGINT.

testpalette:
	"SDL error: blitting boat: Blit combination not supported."  Happens on Mac OS X as well.

testsprite2: 
	SDL_CreateTextureFromSurface requests an ARGB pixel format, but iPhone's SDL video driver only supports ABGR.

testwin:
	Behaves as it does under Mac OS X ... not sure if that is correctly or not.

threadwin:
	Works if -threaded is not on.  Otherwise it doesn't work, but this is true under Mac OS X as well.