This patch modifies tsan_interceptors.cc to be buildable on OS X. Several of the intercepted methods are not available on OS X, so we need to #if !SANITIZER_MAC them. Plus a few other fixes, e.g. pthread_yield doesn't exist, let's use internal_sched_yield instead.
This is part of an effort to port TSan to OS X, and it's one the very first steps. Don't expect TSan on OS X to actually work or pass tests at this point.