anchor.diff:    (multiple-value-bind (str win)
         (prev-history *minibuf-read-line-history*)
       (when win
  -      (buffer-erase)
  +      (minibuffer-clear-input)
         (insert-string str))))
   
   (define-command minibuf-read-line-next-history () ()
     (multiple-value-bind (str win)
         (next-history *minibuf-read-line-history*)
       (when win
  -      (buffer-erase)
  +      (minibuffer-clear-input)
         (insert-string str))))
   
   (define-command minibuf-read-line-break () ()
  
positive.code: (defvar *minibuf-window*)
  (defvar *minibuffer-calls-window*)
  (defvar *minibuffer-start-point* (make-min-point))
  
  (defun minibuffer-window () *minibuf-window*)
  (defun minibuffer-window-p (window) (eq window (minibuffer-window)))
  
negative.code:                       (minibuf-point-charpos)
                        (1- (minibuf-point-linum))))
  
  (defun minibuf-read-line-loop (comp-f existing-p)
    (let ((*minibuf-read-line-existing-p* existing-p)
          (*minibuf-read-line-comp-f* comp-f))
      (catch 'minibuf-read-line-end
  