Summary: This patch implements the solution for LWG Issue #2367. See http://cplusplus.github.io/LWG/lwg-active.html#2367 Reviewers: mclow.lists, EricWF Subscribers: cfe-commits Differential Revision: http://reviews.llvm.org/D13750 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@256325 91177308-0d34-0410-b5e6-96231b3b80d8