Allow libc++ to be built with GCC 5.0 compiler

Differential Revision: http://reviews.llvm.org/D5169

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@217038 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 5907f03123a9b8bc2e31fd671fc5eeae1dd8dc73)
Change-Id: I8d9f2496c587b8eda7906e08bf3db218db642f20
1 file changed