Fix crash when exporting functions with const enums #2384 (#2414)

* headers: handle const enums in exported signatures as base type

* update releasenotes.md

---------

Co-authored-by: Christoffer Lerno <christoffer@aegik.com>

releasenotes.md

@@ -48,6 +48,7 @@
 - Occasionally when using macro method extensions on built-in types, the liveness checker would try to process them. #2398
 - Miscompilation of do-while when the while starts with a branch #2394.
 - Compiler assert when calling unassigned CT functions #2418.
+- Fixed crash in header generation when exporting functions with const enums (#2384).
 
 ### Stdlib changes
 - Add `==` to `Pair`, `Triple` and TzDateTime. Add print to `Pair` and `Triple`.

src/compiler/headers.c

@@ -553,7 +553,9 @@ RETRY:
 			header_gen_enum(c, 0, type->decl);
 			return;
 		case TYPE_CONST_ENUM:
-			TODO;
+			// TODO;
+			type = type_flatten(type);
+			goto RETRY;
 		case TYPE_FUNC_RAW:
 			UNREACHABLE
 		case TYPE_STRUCT: