config: MSVC 19+ has unicode chars

MSVC 19+ and clang-cl with emulation version >= 19.00 will provide
char{16,32}_t as builtin types.  Adjust the configuration accordingly.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290940 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed