anchor.diff:                              (move-point (current-point) minibuf-buffer-prev-point)
                               (when (= 1 *minibuf-read-line-depth*)
                                 (run-hooks *minibuffer-deactivate-hook*)
  -                              (%switch-to-buffer *echoarea-buffer* nil nil)
  -                              ))))))
  +                              (%switch-to-buffer *echoarea-buffer* nil nil)))))))
                   (editor-abort (c)
                     (error c))))))
         (if (eq result +recursive-minibuffer-break-tag+)
  
positive.code:   (let ((result (prompt-for-line
                   prompt
                   ""
                   'completion-buffer-name
                   (and existing
                        (lambda (name)
                          (member name (buffer-list) :test #'string= :key #'buffer-name)))
  
negative.code: (export '(*enable-recursive-minibuffers*
            *minibuffer-completion-function*
            *minibuffer-file-complete-function*
            *minibuffer-buffer-complete-function*
            *minibuffer-activate-hook*
            *minibuffer-deactivate-hook*
            *minibuf-keymap*
  