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

[Kostya Serebryany via llvm-commits]

kcc added a comment.

Or maybe just grab a mutex around CurrentUnitData/CurrentUnitSize
and see how much it affects performance on e.g. test/FullCoverageSetTest.cpp
If not much, just use a mutex.


http://reviews.llvm.org/D20461