Michael van der Westhuizen:  Patches for Linux.  Fixes http://llvm.org/bugs/show_bug.cgi?id=14648.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@172435 91177308-0d34-0410-b5e6-96231b3b80d8
Michael van der Westhuizen: Improve support for testing on Linux.  Fixes http://llvm.org/bugs/show_bug.cgi?id=14892.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@172436 91177308-0d34-0410-b5e6-96231b3b80d8