David Chisnall:  macro protect 'test' in __has_pointer_type_imp.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@191126 91177308-0d34-0410-b5e6-96231b3b80d8
N3659: Shared locking in C++  Revision 2, c++1y only

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@191127 91177308-0d34-0410-b5e6-96231b3b80d8