[PATCH] D20461: [LibFuzzer] Fix sending SIGALRM to main thread under Mac OSX

[Kostya Serebryany via llvm-commits]

kcc added a comment.

I think I've fixed this in r270945.
This part is tricky because it involves both threads and signals, 
so I tried to make it simpler.


http://reviews.llvm.org/D20461