anchor.diff:  
   (defmethod instance-finalizer ((instance gobject))
     (let ((location (proxy-location instance)))
  -    #+gtk2.8
  +    #+glib2.8
       (if (slot-value (class-of instance) 'instance-slots-p)
   	#'(lambda ()
   	    (remove-cached-instance location)
  
positive.code:       #'(lambda ()
  	  (remove-cached-instance location)
  	  (%object-unref location)))
      #-gtk2.8
      #'(lambda ()
  	(remove-cached-instance location)
  	  (%object-unref location))))
  
negative.code: 
  (defmethod reference-foreign ((class gobject-class) location)
    (declare (ignore class))
    #+glib2.8
    (if (slot-value class 'instance-slots-p)
        (%object-add-toggle-ref location)
      (%object-ref location))
    #-glib2.8
    (%object-ref location))
  
  (defmethod unreference-foreign ((class gobject-class) location)
  