Add hb_unicode_combining_class_t
diff --git a/src/hb-unicode-private.hh b/src/hb-unicode-private.hh
index ba791eb..6ec0a76 100644
--- a/src/hb-unicode-private.hh
+++ b/src/hb-unicode-private.hh
@@ -55,7 +55,7 @@
/* Simple callbacks are those taking a hb_codepoint_t and returning a hb_codepoint_t */
#define HB_UNICODE_FUNCS_IMPLEMENT_CALLBACKS_SIMPLE \
- HB_UNICODE_FUNC_IMPLEMENT (unsigned int, combining_class) \
+ HB_UNICODE_FUNC_IMPLEMENT (hb_unicode_combining_class_t, combining_class) \
HB_UNICODE_FUNC_IMPLEMENT (unsigned int, eastasian_width) \
HB_UNICODE_FUNC_IMPLEMENT (hb_unicode_general_category_t, general_category) \
HB_UNICODE_FUNC_IMPLEMENT (hb_codepoint_t, mirroring) \
