[boost] [config] Macro for "using" type alias defects

Hi all, I was wondering if there is any macro in Boost.Config for advertising the defect of the "using" support from the compiler. I was reported this: https://github.com/boostorg/test/pull/140 and at the time I wrote the thing, I thought that those guards would have been enough: https://github.com/boostorg/test/blob/35c9acf5bd38d625ebd45cf940c5b9a19aa229... (auto, tuple and variadic template sounds to me more difficult to support than "using" template alias). Would it make sense to have BOOST_NO_CXX11_TYPE_ALIAS? Thanks, Raffi