Pull new version of libc++ into vendor branch.
Import new libc++.  This contains some fixes for code compiled in c++98 / c++03
mode.
Import new libc++ to vendor branch.
Vendor import of libc++ trunk r180598.
Pull new libc++ into vendor branch.
Vendor import of libc++ tags/RELEASE_34/final r197960:
https://llvm.org/svn/llvm-project/libcxx/tags/RELEASE_34/final@197960
Fix the name of the dts file for the HL201...
Import libc++ 3.4 release.  This contains a lot of bugfixes, and some
preliminary support for C++1y.

MFC after:	3 weeks
Bump copyright dates