[PATCH] [libcxx] Change _LIBCXX_CONSTEXPR_AFTER_CXX11 to check for relaxed constexpr rules

[Marshall Clow]

I don't like the name "relaxed constexpr". What if (as seems likely) the restrictions on constexpr get loosened (again) for C++17?

How about _LIBCXX_IMPLEMENTS_CXX14_CONSTEXPR  instead?

P.S.  Any idea on when gcc will implement this part of C++14? Might it be in 4.9.1? [ I will ping someone on the gcc side and try to find out ]

http://reviews.llvm.org/D4396