anchor.diff:  
   ;;; To determine if a slot should be initialized with the initform,
   ;;; CLISP checks whether it is unbound or not. This doesn't work with
  -;;; virtual slots which does not have an unbound state, so we have to
  +;;; virtual slots that does not have an unbound state, so we have to
   ;;; implement initform initialization in a way similar to how it is
   ;;; done in PCL.
   #+clisp
  
positive.code: 	  (error 'unreadable-slot :name (slot-definition-name slotd) :instance object))
      (let ((reader-function (call-next-method)))
        (cond
         ;; Don't create an wrapper to signal unbound value
         ((not signal-unbound-p) reader-function)
         
         ;; An explicit boundp function has been supplied
  
negative.code: ;; TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  ;; SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  
  ;; $Id: virtual-slots.lisp,v 1.4 2006-09-05 13:16:18 espen Exp $
  
  (in-package "GFFI")
  
  