[PATCH] [Tsan] Fix the thread_name tests to build on FreeBSD

[Dmitry Vyukov]

> Also, do we have the list of annotations documented or described anywhere? Shouldn't we make a public header containing them at some point? Forcing users to declare them with "extern "C"" is ugly.

Please don't make annotations any more convenient to use. They are ugly and they should feel ugly.

http://reviews.llvm.org/D5855