server: Add infrastructure for ioctl server request.
diff --git a/server/request.c b/server/request.c
index 404dda0..4c4036a 100644
--- a/server/request.c
+++ b/server/request.c
@@ -108,6 +108,7 @@
     master_socket_poll_event,      /* poll_event */
     NULL,                          /* flush */
     NULL,                          /* get_fd_type */
+    NULL,                          /* ioctl */
     NULL,                          /* queue_async */
     NULL,                          /* reselect_async */
     NULL                           /* cancel_async */