anchor.diff:  
   (defun setup-redirections (file-actions stdin stdout stderr)
     (let (infd infd-child outfd outfd-child errfd errfd-child)
  +    ;; Standard input
       (if (eql :pipe stdin)
           (setf (values infd infd-child)
  -              (redirect-to-pipes +stdin+ file-actions t))
  -        (redirect-one-stream stdin +stdin+ file-actions isys:o-rdonly))
  +              (redirect-to-pipes file-actions +stdin+ t))
  +        (redirect-one-stream file-actions +stdin+ stdin isys:o-rdonly))
  +    ;; Standard output
       (if (eql :pipe stdout)
           (setf (values outfd outfd-child)
  -              (redirect-to-pipes +stdout+ file-actions nil))
  -        (redirect-one-stream stdout +stdout+ file-actions isys:o-wronly))
  +              (redirect-to-pipes file-actions +stdout+ nil))
  +        (redirect-one-stream file-actions +stdout+ stdout (logior isys:o-wronly
  +                                                                  isys:o-creat)))
  +    ;; Standard error
       (cond
         ((and stdout (eql :stdout stderr))
  -       (redirect-one-stream +stdout+ +stderr+ file-actions 0 nil))
  +       (redirect-one-stream file-actions +stderr+ +stdout+))
         ((eql :pipe stderr)
          (setf (values errfd errfd-child)
  -             (redirect-to-pipes +stderr+ file-actions nil)))
  +             (redirect-to-pipes file-actions +stderr+ nil)))
         (t
  -       (redirect-one-stream stderr +stderr+ file-actions isys:o-wronly)))
  +       (redirect-one-stream file-actions +stderr+ stderr (logior isys:o-wronly
  +                                                                 isys:o-creat))))
       (values infd infd-child outfd outfd-child errfd errfd-child)))
   
   (defun close-fds (&rest fds)
  
positive.code:       (null
         (lfp-spawn-file-actions-addclose file-actions fd)))))
  
  (defun redirect-to-pipes (fd file-actions keep-write-fd)
    (declare (notinline isys:pipe))
    (multiple-value-bind (pipe-parent pipe-child)
        (isys:pipe)
  
negative.code:                   ,@body))
             (deallocate-null-ended-list ,argv))))))
  
  (defun redirect-one-stream (file-actions fd stream &optional flags (mode #o644) close-old-fd)
    (declare (notinline lfp-spawn-file-actions-addopen
                        lfp-spawn-file-actions-adddup2
                        lfp-spawn-file-actions-addclose))
    (flet ((dup-from-path (path)
             (lfp-spawn-file-actions-addopen file-actions fd path flags mode))
           (dup-from-fd (oldfd)
             (lfp-spawn-file-actions-adddup2 file-actions oldfd fd)
             (when close-old-fd
  