consts: include *all* names;

--- a/src/Pure/Syntax/syn_ext.ML	Mon Jul 17 18:17:54 2000 +0200
+++ b/src/Pure/Syntax/syn_ext.ML	Mon Jul 17 21:44:39 2000 +0200
@@ -311,7 +311,7 @@
     SynExt {
       logtypes = logtypes',
       xprods = xprods,
-      consts = filter Lexicon.is_xid (consts union mfix_consts),
+      consts = consts union mfix_consts,
       prmodes = distinct (map (fn (m, _, _) => m) tokentrfuns),
       parse_ast_translation = parse_ast_translation,
       parse_rules = parse_rules,