anchor.diff:    (x-root :int) (y-root :int)
     (state :unsigned-int)
     (button :unsigned-int)
  -  (same-screen bool))
  +  (same-screen :boolean))
   
   (defctype x-button-pressed-event x-button-event)
   (defctype x-button-released-event x-button-event)
  
positive.code: (defcstruct x-expose-event
    (type :int)
    (serial :unsigned-long)
    (send-event bool)
    (display-ptr :pointer)
    (win window)
    (x :int) (y :int)
  
negative.code:   (border-pixmap pixmap) (border-pixel :unsigned-long)
    (bit-gravity :int) (win-gravity :int) (backing-store :int)
    (backing-planes :unsigned-long) (backing-pixel :unsigned-long)
    (save-under :boolean) (event-mask :long) (do-not-propagate-mask :long)
    (override-redirect :boolean) (cmap colormap) (curs cursor))
  
  (defcenum (x-alloc :int)
    (:alloc-none)
  