1. added:
    (require (lib "file.ss"))


    2. added:
    (xdef 'make-directory make-directory)
    (xdef 'make-directory* make-directory*)

    (def mkdir (path (o parents))
         (if (is parents nil)
             (make-directory path)
             (make-directory* path))
    )

    (def ensure-dir (path)
        (unless (dir-exists path)
             (mkdir path t)))