The Tao team has dropped the ball on Mac OS X support, so people distributing for that OS must provide the necessary support for AutoreleasePool and the others.
This would already be added, except I can't figure out how to create a Tao.Sdl application with AutoreleasePool that properly exits. It seems to get stuck somehow... right now Process.Kill is the only way around it.
As well, there's a question of where to put the code that initializes AutoreleasePool and kills the program; Window seems the most obvious choice but it may be difficult to manage its lifetime.