anchor.diff:  ;;;
   ;;; SLOT-BOUNDP-USING-CLASS
   
  -(defun slot-boundp-using-class-default (object slot)
  +(defun slot-boundp-using-class-default (class object slot)
  +  (declare (ignore class))
     (let ((location (slot-definition-location slot)))
       (not (eq (if (consp location)
   		 (car location)
  
positive.code: (defun find-slot (object slot-name)
    (let* ((class (class-of object))
  	 (slots (class-slots class)))
      (find slot-name slots :test #'eq :key #'slot-name)))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  
negative.code: ;;;
  ;;; SLOT-MAKUNBOUND, SLOT-MAKUNBOUND-USING-CLASS.
  
  (defun slot-makunbound-using-class-default (class object slot)
    (declare (ignore class))
    (let ((location (slot-definition-location slot)))
      (if (consp location)
  	(setf (car location) *unbound-value*)
  