[tsan] Port TSan interceptors on OS X

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.

Differential Revision: http://reviews.llvm.org/D14237

llvm-svn: 251916