[boost] [Boost] [Config] Macros for the absence of a full C++11 <memory> implementation

Macros to determine the availability of C++11 functions in <memory> like std::align would be useful to me. (I know that declaration begs the inquiry "What conforming code would you write if std::align is not present?" but that is separate e-mail...) Would a BOOST_NO_CXX11_HDR_MEMORY be generally useful? Glen