implement robust mutexes
some of this code should be cleaned up, e.g. using macros for some of
the bit flags, masks, etc. nonetheless, the code is believed to be
working and correct at this point.
diff --git a/include/pthread.h b/include/pthread.h
index d40002e..e15f25b 100644
--- a/include/pthread.h
+++ b/include/pthread.h
@@ -92,6 +92,7 @@
int pthread_mutex_trylock(pthread_mutex_t *);
int pthread_mutex_timedlock(pthread_mutex_t *, const struct timespec *);
int pthread_mutex_destroy(pthread_mutex_t *);
+int pthread_mutex_consistent(pthread_mutex_t *);
int pthread_cond_init(pthread_cond_t *, const pthread_condattr_t *);
int pthread_cond_destroy(pthread_cond_t *);