allow extern + hlNative on class

src/generators/genhl.ml

@@ -3530,7 +3530,7 @@ let add_types ctx types =
 						match f.cf_kind with
 						| Method MethNormal when not (List.exists (fun (m,_,_) -> m = Meta.Custom ":hlNative") f.cf_meta) ->
 							(match f.cf_expr with
-							| Some { eexpr = TFunction { tf_expr = { eexpr = TBlock ([] | [{ eexpr = TReturn (Some { eexpr = TConst _ })}]) } } } ->
+							| Some { eexpr = TFunction { tf_expr = { eexpr = TBlock ([] | [{ eexpr = TReturn (Some { eexpr = TConst _ })}]) } } } | None ->
 								let name = prefix ^ String.lowercase (Str.global_replace (Str.regexp "[A-Z]+") "_\\0" f.cf_name) in
 								f.cf_meta <- (Meta.Custom ":hlNative", [(EConst (String lib),p);(EConst (String name),p)], p) :: f.cf_meta;
 							| _ -> ())