DragonFlyBSD

diff --git a/lib/libthread_xu/thread/thr_mutex.c b/lib/libthread_xu/thread/thr_mutex.c

index 3ddfacc..617d821 100644

--- a/lib/libthread_xu/thread/thr_mutex.c

+++ b/lib/libthread_xu/thread/thr_mutex.c

@@ -213,8 +213,10 @@ _pthread_mutex_destroy(pthread_mutex_t *mutex)

pthread_mutex_t m;

int ret = 0;

- if (mutex == NULL || *mutex == NULL)

+ if (mutex == NULL)

ret = EINVAL;

+ else if (*mutex == NULL)

+ ret = 0;

else {

/*

* Try to lock the mutex structure, we only need to