had an extra underscore

kern/synchprobs/traffic_synch.c

@@ -123,7 +123,7 @@ static void clearint(car * done)
     //cv_broadcast(temp->cv, globlock); // wake all/inform them you're all good
     //cv_destroy(temp->cv);
     
-    while (!(wchan_is_empty(temp->cv->wc)))
+    while (!(wchan_isempty(temp->cv->wc)))
     {
       cv_signal(temp->cv, globlock);
     }