[Bug c++/50196] std::thread can not use under macos.

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50196

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-08-26 16:06:00 UTC ---
It would be possible to define _GLIBCXX_HAS_GTHREADS without _POSIX_TIMEOUTS,
so that <thread> is available, and most of <mutex> too.  I think only the Timed
Mutex types require _POSIX_TIMEOUTS, so there's a lot of useful functionality
that doesn't require it.

We could have _GLIBCXX_HAS_GTHREADS and _GLIBCXX_HAS_TIMED_MUTEXES, with only
the second depending on _POSIX_TIMEOUTS