diff --git a/sys/sys/lockf.h b/sys/sys/lockf.h
index cded00f686b..836c7a999c7 100644
--- a/sys/sys/lockf.h
+++ b/sys/sys/lockf.h
@@ -44,7 +44,9 @@
 
 struct vop_advlock_args;
 
+#ifdef MALLOC_DECLARE
 MALLOC_DECLARE(M_LOCKF);
+#endif
 
 /*
  * The lockf structure is a kernel structure which contains the information