cmake: remove --as-needed linker flag for Mac OS X
cmake: clean up BuildBoost
cmake/Boost: add Mac OS X support
cmake/patch: remove --merge switch, because mac os x can't handle that

I've tested it on Mac OS X 10.7, which is farily new, don't know if we can use it on 10.8
cmake/v8: clean up
cmake/wxWidgets: add Mac OS X support
common: add Mac OS X support
threads: add Mac OS X support
git: ignore .DS_Store files
util: add basic Mac OS X support
util_fs: add Mac OS X support