anchor.diff:    (native-namestring (merge-pathnames pathname)))
   
   (defun call-in-temporary-directory (template-pathname fun)
  +  "Call FUN with the POSIX cwd and *DEFAULT-PATHNAME-DEFAULTS* set to
  +a temporary directory that is unconditionally deleted when FUN
  +returns, either normally or via a non-local exit."
     (flet ((random-temporary ()
              (let* ((parts (pathname-directory template-pathname))
                     (last (first (last parts)))
  
positive.code: 
  (defvar *command-output* (make-synonym-stream '*standard-output*))
  
  (defun stringify-command-argument (argument)
    (typecase argument
      (string argument)
      (pathname (native-namestring argument))
  
negative.code:     (let ((code (process-exit-code process)))
        (if (zerop code)
            t
            ;; FIXME: Raise a proper condition that can be handled.
            (error "Command exited with non-zero status ~D" code)))))
  
  (defmacro with-run-output ((stream (command &rest args)) &body body)
    "Bind STREAM to the output stream of COMMAND and evaluate BODY."
    `(let* ((*command-output* (make-string-output-stream)))
       (run ,command ,@args)
       (with-input-from-string (,stream (get-output-stream-string  *command-output*))
  