diff --git a/src/hb-ot-var.h b/src/hb-ot-var.h
index 997be77f1..676be9f7b 100644
--- a/src/hb-ot-var.h
+++ b/src/hb-ot-var.h
@@ -98,7 +98,9 @@ hb_ot_var_find_axis (hb_face_t        *face,
  * Since: REPLACEME
  */
 typedef enum { /*< flags >*/
-  HB_OT_VAR_AXIS_FLAG_HIDDEN	= 0x0001u,
+  HB_OT_VAR_AXIS_FLAG_HIDDEN	= 0x00000001u,
+
+  _HB_OT_VAR_AXIS_FLAG_MAX_VALUE= 0x7FFFFFFFu, /*< skip >*/
 } hb_ot_var_axis_flags_t;
 
 HB_EXTERN hb_ot_var_axis_flags_t