anchor.diff:  ;; 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 ?
  +;; memo
  +;; bin/mingw-get.exe install msys-base
  +;; bin/mingw-get.exe install mingw32-gcc
  +;; bin/mingw-get.exe install mingw32-autoconf (is needed?)
  +
  +;; write /etc/fstab C:/Users/Vagrant/.roswell/impls/x86/windows/msys/-/     /mingw
  +;; ensure ros's path in  env PATH
  +;; instead of "sh" "sh -l" to use for WIN32.
   
   (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"
  
positive.code:          (progn
             (ros.install::download (format nil "~@{~A~}" "http://prdownloads.sourceforge.net/mingw/" file "?download")
                                    path)
             (format t " done.~%"))))
    (cons t argv))
  
  (setq *install-cmds*
        (list
  
negative.code:   (let* ((pos (position #\/ *7za-archive* :from-end t))
           (pos2 (when pos
                   (position #\/ *7za-archive* :from-end t :end 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)
    (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...~%")
  