anchor.diff:        (null
          (lfp-spawn-file-actions-addclose file-actions fd)))))
   
  -(defun redirect-to-pipes (fd file-actions keep-write-fd)
  +(defun redirect-to-pipes (file-actions fd keep-write-fd)
     (declare (notinline isys:pipe))
     (multiple-value-bind (pipe-parent pipe-child)
         (isys:pipe)
  
positive.code: 
  (defun setup-redirections (file-actions stdin stdout stderr)
    (let (infd infd-child outfd outfd-child errfd errfd-child)
      (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))
      (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))
      (cond
        ((and stdout (eql :stdout stderr))
         (redirect-one-stream +stdout+ +stderr+ file-actions 0 nil))
        ((eql :pipe stderr)
         (setf (values errfd errfd-child)
               (redirect-to-pipes +stderr+ file-actions nil)))
        (t
         (redirect-one-stream stderr +stderr+ file-actions isys:o-wronly)))
      (values infd infd-child outfd outfd-child errfd errfd-child)))
  
  (defun close-fds (&rest fds)
  
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
  