the following types of mutex:
(pthread_mutex_lock): Process the lock request
according to the mutex type.
* mutex.c: No longer use Win32 mutexes as the
basis of POSIX mutexes when TryEnterCriticalSection
isn't supported; implement our own versions of
functions to emulate TryEnterCriticalSection when
it isn't supported by the system; don't allow recursive
mutex locks (similar to PTHREAD_MUTEX_ERRORCHECK
on other systems).
- Thomas Pfaff <email@example.com>