anchor.diff:                           :if-does-not-exist :create
                            :if-exists nil)
           (format o "~S~%" v))))
  -  (cons (not (get-opt "without-install")) argv))
  +  (cons (not (get-opt "until-extract")) argv))
   
   (defun sbcl-patch (argv)
     #+darwin
  
positive.code: 
  (defun sbcl-msys (argv)
    (unless (or (ros:getenv "MSYSCON")
                (get-opt "without-install"))
      (ros:roswell '("install msys2+") :interactive nil))
    (cons t argv))
  
  
negative.code:     (set-opt "install.force" "t")
      (set-opt "archive" "t"))
    (when (position "--without-install" (getf argv :argv) :test 'equal)
      (set-opt "until-extract" t))
    (set-opt "prefix" (merge-pathnames (format nil "impls/~A/~A/~A/~A/" (uname-m) (uname) (getf argv :target) (get-opt "as")) (homedir)))
    (set-opt "src" (merge-pathnames (format nil "src/~A-~A/" (getf argv :target) (getf argv :version)) (homedir)))
    (labels ((with (opt)
  