anchor.diff:     (id :accessor win32-window-id)))
   
   #+(or win32 windows)
  -(defstruct (win32-video-mode (:include video-mode)))
  +(defstruct (win32-video-mode (:include video-mode))
  +  (rate 0 :type integer))
   
   #+(and unix (not darwin))
   (defclass x11-window ()
  
positive.code: 
  #+darwin
  (defstruct (osx-video-mode (:include video-mode))
    mode)
  
  ;; base window structure
  
negative.code: 
  #+(and unix (not darwin))
  (defstruct (x11-video-mode (:include video-mode))
    (rate 0 :type integer)
    (index -1 :type integer))
  
  #+darwin
  