anchor.diff:    ;; OK ...
   
     (subtypep (make-instance (find-class 'frob-s-1)) 'frob-c)
  -  ;; FIXME => NIL, T
  +  ;; NB => NIL, T ;; FIXME - BREAKS in CCL (??)
     ;;
     ;; ^ T.D: Dispatch in INITIALIZE-INSTANCE SINGLETON ??
     ;;
  
positive.code: 
  ;; --
  
  (defgeneric class-prototype-metaclass (class)
    (:method ((class singleton))
      ;; FIXME - Handle specially when CLASS would be the PROTOTYPE-CLASS class
  
negative.code: 
  
  (subtypep (make-instance 'singleton-1-1) 'singleton-1-1)
  ;; => NIL, T
  
  (subtypep (make-instance 'singleton-2-2) 'singleton-1-1)
  ;; => NIL, T
  
  (subtypep (make-instance 'singleton-2-2
                           :direct-superclasses
                           (list (find-class 'singleton-2-2)))
            'singleton-1-1)
  ;; => T, T
  
  (typep (make-instance 'singleton-2-2) 'singleton-1-1)
  ;; => T
  ;; OK !
  
  
  ;; NB: To produce a suclass C2 of a class C1, such that C2 is both an
  