anchor.diff:  
   ;;; Symbols directly imported from package CL-USER.
   (defconstant +direct-imports+
  -    '(nil t not eq eql atom setq quote
  +    '(nil t eq eql atom setq quote
         cons car cdr rplaca rplacd
         apply function
         progn block return return-from tagbody go
  
positive.code: 
  ;;; Things we have to implement ourselves.
  (defconstant +implementations+
      '(%set-atom-fun cpr rplacp %load atan2 pow quit string-concat %load
        %eval %defun early-defun %defvar %defmacro %string %make-symbol
        %symbol-name %symbol-value %symbol-function %symbol-package
        %number? == %integer %+ %- %* %/ %< %>
  
negative.code: (defun eval (x) (%eval x))
  (defun macroexpand (x) (%%macroexpand x))
  (defun string (x) (%string x))
  (defun not (&rest x) (apply #'%not x))
  (defun make-symbol (x) (%make-symbol x))
  (defun symbol-value (x) (%symbol-value x))
  (defun symbol-function (x) (%symbol-function x))
  