diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -5298,7 +5298,7 @@
 /*
  * Routine to create and manage a filesystem syncer vnode.
  */
-#define sync_close ((int (*)(struct  vop_close_args *))nullop)
+static int	sync_close(struct vop_close_args *);
 static int	sync_fsync(struct  vop_fsync_args *);
 static int	sync_inactive(struct  vop_inactive_args *);
 static int	sync_reclaim(struct  vop_reclaim_args *);
@@ -5392,6 +5392,12 @@
 		vrele(vp);
 }
 
+static int
+sync_close(struct vop_close_args *args __unused)
+{
+	return (0);
+}
+
 /*
  * Do a lazy sync of the filesystem.
  */