anchor.diff:  (defun minibuffer-window-p (window)
     (typep window 'sticky-minibuffer-window))
   (defun minibuffer-window-active-p () (eq (current-window) (minibuffer-window)))
  -(defun minibuffer-window-height () *minibuffer-window-height*)
   (defun minibuffer () (window-buffer (minibuffer-window)))
   (defun minibufferp (buffer) (eq buffer (minibuffer)))
   
  
positive.code:           minibuffer-read-line-prev-history
            minibuffer-read-line-next-history))
  
  (defparameter *minibuffer-window-height* 1)
  (defvar *enable-recursive-minibuffers* nil)
  
  (defvar +recursive-minibuffer-break-tag+ (gensym))
  
negative.code:                  :buffer buffer
                   :x 0
                   :y (- (display-height)
                         +minibuffer-window-height+)
                   :width (display-width)
                   :height +minibuffer-window-height+
                   :use-modeline-p nil
                   :frame frame))
  
  