* pthread.cc (pthread_mutex::_unlock): Avoid unlocking a mutex if the

* pthread.cc (pthread_mutex::_unlock): Avoid unlocking a mutex if the
recursion_counter is already 0.
(pthread_mutex::_destroy): Don't consider a mutex busy if its recursion_counter
== 0.
(pthread_mutex::_fixup_after_fork): Set recursion_counter to 0 to flag that
we've just forked.  Don't reset the owner of this mutex since the forkee may
think it still owns the mutex.  Reinstate initialization of win32_obj_id.
* fhandler_floppy.cc (fhandler_dev_floppy::raw_read): Initialize a variable to
bypass a C++ warning.