anchor.diff:             (set symbol (merge-pathnames (format nil "~A/" impl) (symbol-value symbol))))
             (t (cl:print "tbd.....")))))
   
  +(defparameter *version-cache* nil)
  +(defun version (&optional opt)
  +  (if opt
  +      (roswell `("roswell-internal-use" "version" ,(string-downcase (princ-to-string opt))) :string t)
  +      (or *version-cache*
  +          (setf *version-cache* (roswell '("roswell-internal-use" "version") :string t)))))
  +
   #+sbcl
   (when (ignore-errors (string-equal (opt "impl") "sbcl-bin" :end1 8))
     (let ((path (merge-pathnames (format nil "src/sbcl-~A/" (lisp-implementation-version)) (opt "homedir"))))
  
positive.code: 
  (setf (fdefinition 'load-system)
        #'system)
  
  (defparameter *version-cache* nil)
  (defun version (&optional opt)
    (if opt
        (roswell `("roswell-internal-use" "version" ,(string-downcase (princ-to-string opt))) :string t)
        (or *version-cache*
            (setf *version-cache* (roswell '("roswell-internal-use" "version") :string t)))))
  
  (defun package (cmd arg &rest rest)
    (declare (ignorable cmd rest))
  
negative.code:     (let ((*error-output* (if (verbose)
                                *error-output*
                                (make-broadcast-stream))))
        (setf sentinel
              (or sentinel
                  (when (and (opt "asdf")
                             (or (and (find :asdf *features*)
                                      (not (equal (opt "asdf")
                                                  (funcall (read-from-string "asdf:asdf-version")))))
                                 (not (find :asdf *features*))))
                    (funcall 'asdf :no-download t))
                  (find :asdf *features*)
                  (ignore-errors (require "asdf")))
              sentinel (not (not sentinel))))))
  
  #+(and unix sbcl) ;; from swank
  (progn
  