Add the fact that Clang too is planning to start using C++11 (in some
limited ways) after the next release. See the lengthy discussions (which
are on-going) and the corresponding commit to LLVM's release notes.
Nothing is actually changing at this point, this is just further
spreading the plan.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194184 91177308-0d34-0410-b5e6-96231b3b80d8