[boost] Problem in thread or chrono: boost::this_thread::sleep_for() sometimes returns immediately on win32

Hi, As I've just described in https://svn.boost.org/trac/boost/ticket/9720 I've had a problem with boost::this_thread::sleep_for. I'm guessing that this could be a problem with either chrono or thread. Just thought I'd post here since I don't know how much the devs check the tickets. Cheers Lars