[aat.feat] Add _MAX_VALUE to enums

src/hb-aat-layout.h

@@ -83,7 +83,9 @@ typedef enum
   HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE				= 37,
   HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE				= 38,
   HB_AAT_LAYOUT_FEATURE_TYPE_LANGUAGE_TAG_TYPE			= 39,
-  HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE		= 103
+  HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE		= 103,
+
+  _HB_AAT_LAYOUT_FEATURE_TYPE_MAX_VALUE= 0x7FFFFFFFu, /*< skip >*/
 } hb_aat_layout_feature_type_t;
 
 /**
@@ -420,7 +422,9 @@ typedef enum
   HB_AAT_LAYOUT_FEATURE_SELECTOR_HALF_WIDTH_CJK_ROMAN		= 0,
   HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_CJK_ROMAN		= 1,
   HB_AAT_LAYOUT_FEATURE_SELECTOR_DEFAULT_CJK_ROMAN		= 2,
-  HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_CJK_ROMAN		= 3
+  HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_CJK_ROMAN		= 3,
+
+  _HB_AAT_LAYOUT_FEATURE_SELECTOR_MAX_VALUE= 0x7FFFFFFFu, /*< skip >*/
 } hb_aat_layout_feature_selector_t;
 
 HB_EXTERN unsigned int