Fix typo

src/misc/threads.c

@@ -166,7 +166,7 @@ int vlc_sem_post (vlc_sem_t *sem)
 void vlc_sem_wait (vlc_sem_t *sem)
 {
     vlc_mutex_lock (&sem->lock);
-    mutex_cleanup_push (&lock->mutex);
+    mutex_cleanup_push (&sem->lock);
     while (!sem->value)
         vlc_cond_wait (&sem->wait, &sem->lock);
     sem->value--;