anchor.diff:  collect_form(['extend-module'|Mdef], _, St0) ->
       St1 = collect_mdef(Mdef, St0),
       {[],St1};
  +collect_form(['eval-when-compile'|_], _, St) ->
  +    %% Can safely ignore this, everything already in environment.
  +    {[],St};
   collect_form(['define-function',F,Def], _, St) ->
       Ar = function_arity(Def),
       {[{F,Ar,Def}],St}.
  
positive.code: -import(lfe_env, [new/0,add_env/2,
                    add_vbinding/3,add_vbindings/2,is_vbound/2,get_vbinding/2,
                    fetch_vbinding/2,del_vbinding/2,
                    add_fbinding/4,add_fbindings/3,get_fbinding/3,add_ibinding/5,
                    get_gbinding/3,add_mbinding/3]).
  
  -import(orddict, [store/3,find/2]).
  
negative.code:     foldl(fun (F, {_,S}) -> eval_form_1(F, S) end,
            {[],St}, Eforms);
  eval_form_1(['extend-module'|_], St) ->         %Maybe from macro expansion
      {[],St};
  eval_form_1(['eval-when-compile'|_], St) ->	%Maybe from macro expansion
      %% We can happily ignore this.
      {[],St};
  eval_form_1([set|Rest], St0) ->
      {Value,St1} = set(Rest, St0),
  