Add name_lookup function in object_ops.

diff --git a/server/semaphore.c b/server/semaphore.c
index 650b5b1..589704a 100644
--- a/server/semaphore.c
+++ b/server/semaphore.c
@@ -55,6 +55,7 @@
     semaphore_satisfied,           /* satisfied */
     semaphore_signal,              /* signal */
     no_get_fd,                     /* get_fd */
+    no_lookup_name,                /* lookup_name */
     no_close_handle,               /* close_handle */
     no_destroy                     /* destroy */
 };