MinGW 4.8.1 C++11 thread support

If I understand well, std threading is still not supported on mingw, but some mingw-w64 builds support it. Fortunately, you can still build 32-bit apps using this version of mingw.

Here is the link for the builds.

There is already a native win32 implementation of std::thread and sync primitives: https://github.com/meganz/mingw-std-threads It is a header-only library and should work with any C++11 compliant version of MinGW.