[PATCH] Make io engines -W clean

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/engines/fio-engine-libaio.c b/engines/fio-engine-libaio.c
index 9197107..c3fefda 100644
--- a/engines/fio-engine-libaio.c
+++ b/engines/fio-engine-libaio.c
@@ -17,12 +17,13 @@
 	struct io_event *aio_events;
 };
 
-static int fio_libaio_sync(struct thread_data *td, struct fio_file *f)
+static int fio_libaio_sync(struct thread_data fio_unused *td,
+			   struct fio_file *f)
 {
 	return fsync(f->fd);
 }
 
-static int fio_libaio_prep(struct thread_data *td, struct io_u *io_u)
+static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u)
 {
 	struct fio_file *f = io_u->file;