[libcxx] LWG2420 bits for bind<void> - Patch from K-Ballo

Implemented LWG2420 bits for bind<void>

Review: http://reviews.llvm.org/D10997


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@241967 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed