copy :build metadata to abstract implementation class

typeload.ml

@@ -162,6 +162,7 @@ let make_module ctx mpath file tdecls loadp =
 				let acc = make_decl acc (EClass { d_name = d.d_name ^ "Impl"; d_flags = [HPrivate]; d_data = fields; d_doc = None; d_params = []; d_meta = [] },p) in
 				(match !decls with
 				| (TClassDecl c,_) :: _ ->
+					(try c.cl_meta <- (Meta.get Meta.Build a.a_meta) :: c.cl_meta with Not_found -> ());
 					a.a_impl <- Some c;
 					c.cl_kind <- KAbstractImpl a
 				| _ -> assert false);