Make mailslots use as much of the default async fd implementation as
possible.
diff --git a/server/file.h b/server/file.h
index eed81d8..f89940b 100644
--- a/server/file.h
+++ b/server/file.h
@@ -65,6 +65,7 @@
extern int default_fd_signaled( struct object *obj, struct thread *thread );
extern int default_fd_get_poll_events( struct fd *fd );
extern void default_poll_event( struct fd *fd, int event );
+extern void fd_queue_async_timeout( struct fd *fd, void *apc, void *user, void *io_sb, int type, int count, int *timeout );
extern void default_fd_queue_async( struct fd *fd, void *apc, void *user, void *io_sb, int type, int count );
extern void default_fd_cancel_async( struct fd *fd );
extern int no_flush( struct fd *fd, struct event **event );