Merge r4171: In Lck__Trylock we probably do want to try locks -- and check return value not errno

git-svn-id: http://www.varnish-cache.org/svn/branches/2.0@4300 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_lck.c

@@ -111,8 +111,8 @@ Lck__Trylock(struct lock *lck, const char *p, const char *f, int l)
 	int r;
 
 	CAST_OBJ_NOTNULL(ilck, lck->priv, ILCK_MAGIC);
-	r = pthread_mutex_lock(&ilck->mtx);
-	assert(r == 0 || errno == EBUSY);
+	r = pthread_mutex_trylock(&ilck->mtx);
+	assert(r == 0 || r == EBUSY);
 	if (params->diag_bitmap & 0x8)
 		VSL(SLT_Debug, 0,
 		    "MTX_TRYLOCK(%s,%s,%d,%s) = %d", p, f, l, ilck->w);