more explicit notion of canonized code equations

--- a/src/HOL/Tools/recfun_codegen.ML	Wed Oct 14 12:04:16 2009 +0200
+++ b/src/HOL/Tools/recfun_codegen.ML	Wed Oct 14 12:19:17 2009 +0200
@@ -56,7 +56,7 @@
     raw_thms
     |> preprocess thy
     |> avoid_value thy
-    |> Code_Thingol.clean_thms thy
+    |> Code_Thingol.canonize_thms thy
     |> rpair module_name
   end;