Allow unit testing on Windows
These changes allow testing on Windows using clang.exe.
There are two main changes:
1. Only link to -lm when it actually exists on the system
2. Create basic versions of pthread_create() and pthread_join() for windows.
They are not POSIX compliant by any stretch but will allow any existing
and future tests to use pthread_create() and pthread_join() for testing
interactions of libomp with os threads.
Differential Revision: http://reviews.llvm.org/D20391
llvm-svn: 270464
GitOrigin-RevId: 1ab887d40324a2c2181d0ae02ce6717ad5f2577c
6 files changed
