anchor.diff:  ;;; is expanded.
   
   (define-compiler-macro go (label)
  -  (aif (assoc label *tagbody-replacements*)
  +  (aif (cdr (assoc label *tagbody-replacements*))
       `(vm-go ,!)
       (with-gensym g
         (acons! label g *tagbody-replacements*)
  
positive.code:      ,@(mapcar #'((x)
   	                (if (consp x)
  		     		    x
  		     			(aif (assoc x *tagbody-replacements*)
  		       				!
  		       				x)))
                 args)
  
negative.code:                       ,@(if (vm-jump? (car tail))
  						    tail
  						    `((%setq ~%ret ,@tail)))))
               (bname (cdr (assoc block-name *blockname-replacements*))))
          (if bname
              (nconc ret (list bname) '((identity ~%ret)))
              (nconc ret '((identity ~%ret)))))
  