tsan: support sigsuspend() call
Intercepting it makes it process pending signal before return.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@186400 91177308-0d34-0410-b5e6-96231b3b80d8
[ASan] Bump min supported Mac OS X version to 10.6

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@186404 91177308-0d34-0410-b5e6-96231b3b80d8