Is it possible to implement boost::thread_specific_ptr via thread_local?

This problem may looks strange. I want to do that because we have some code need to be built on several platforms, but some platform doesn't support thread_local, then use boost::thread_specific_ptr instead. however, it's unpleasing to build boost binary for every platform (x86/x64/arm, debug/release, os, too many).

I wonder if it's possible to imp thread_specific_ptr via thread_local so that we can keep client code more elegant(avoid #ifdef)

I want to have a header file like:

#if HAS_THREAD_LOCAL
class thread_specific_ptr
{
    ... // use thread_local to implement
};
#else
using boost::thread_specific_ptr
#endif

I can't find the way, maybe you can, thanks.