anchor.diff:    (let* ((pos (position #\/ *7za-archive* :from-end t))
            (pos2 (when pos
                    (position #\/ *7za-archive* :from-end t :end pos)))
  -         (version (when pos2 (subseq *7za-archive* (1+ pos2) pos)))
  +         (pos3 (when pos2
  +                 (position #\/ *7za-archive* :from-end t :end pos2)))
  +         (version (when pos2 (subseq *7za-archive* (1+ pos3) pos2)))
            (prefix (merge-pathnames (format nil "impls/~A/~A/~A/~A/" (uname-m) (uname) "7za" version) (homedir))))
       (values (merge-pathnames "7za.exe" prefix) version)))
   
   (defun un7za (path output-path)
  -  (format nil "7za x ~A -so |7za x -ttar -si -y -o ~A"
  -          path
  -          output-path))
  +  (uiop/run-program:run-program
  +   (format nil "~A x ~A -so |~A x -ttar -si -y -o~A"
  +           (uiop/filesystem:native-namestring (7za))
  +           (uiop/filesystem:native-namestring path)
  +           (uiop/filesystem:native-namestring (7za))
  +           (uiop/filesystem:native-namestring output-path))))
   
   (defun msys-setup-7za (argv)
     (format t "setting up 7zip...~%")
  
positive.code: ;; strategy to obtain toolchain for windows
  ;; sbcl-bin -> quicklisp(until here should be finished when this file is loaded)
  ;; -> zip:unzip -> 7za.exe -> mingw-get
  ;; reference for mingw-get : https://chocolatey.org/packages/mingw-get ?
  
  (defvar *7za-archive* "http://sourceforge.net/projects/sevenzip/files/7-Zip/9.20/7za920.zip/download#")
  (defvar *mingw-get-files* '("mingw-get-0.6.2-mingw32-beta-20131004-1-bin.tar.xz"
  
negative.code:          (progn
             (ros.install::download (format nil "~@{~A~}" "http://prdownloads.sourceforge.net/mingw/" file "?download")
                                    path)
             (format t " done.~%")))
       (format t "extract")
       (un7za path (ensure-directories-exist
                    (merge-pathnames (format nil "impls/~A/~A/~A/~A/" (uname-m) (uname) "msys" "-") (homedir))))
       (format t " done ~%"))
    (cons t argv))
  
  ;;(msys-setup-msys t)
  
  (setq *install-cmds*
        (list
  