diff --git a/lib/libc/yp/yplib.c b/lib/libc/yp/yplib.c
index 3ba6b3fcb7e..2b87d306f50 100644
--- a/lib/libc/yp/yplib.c
+++ b/lib/libc/yp/yplib.c
@@ -105,7 +105,7 @@ struct dom_binding *_ypbindlist;
 static char _yp_domain[MAXHOSTNAMELEN];
 int _yplib_timeout = 10;
 
-static mutex_t _ypmutex = PTHREAD_MUTEX_INITIALIZER;
+static mutex_t _ypmutex = MUTEX_INITIALIZER;
 #define YPLOCK()	mutex_lock(&_ypmutex);
 #define YPUNLOCK()	mutex_unlock(&_ypmutex);