[boost] [config] Macro for detecting thread_local storage support

I have looked but been unable to find any macro in Boost.Config for detecting compiler support for the C++11 thread_local storage specifier. Does such functionality exist? I would like to use something like this to automatically detect compiler support for thread_local for use by the proposed Boost.Compute library. Currently I rely on the users defining BOOST_COMPUTE_HAVE_THREAD_LOCAL in order to enable support. Hopefully there is a better way? -kyle