anchor.diff:                                    (merge-pathnames (format nil "archives/~A" (subseq (get-opt "download.uri") (1+ pos))) (homedir)))))
     (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 default)
  +             (set-opt opt
  +                      (cond ((position (format nil "--with-~A" opt) (getf argv :argv) :test 'equal) t)
  +                            ((position (format nil "--without-~A" opt) (getf argv :argv) :test 'equal) nil)
  +                            (t default)))))
  +    (with "thread" t)
  +    (with "core-compression" t)
  +    (with "ldb" nil)
  +    (with "xref-for-internals" nil))
     (cons t argv))
   
   (defun sbcl-start (argv)
  
positive.code:             'start
              'sbcl-download
              'sbcl-expand
              'sbcl-make
              'sbcl-install
              'setup))
  
negative.code:           (merge-pathnames "src/" (homedir)))
    (cons t argv))
  
  (defun sbcl-config (argv)
    (with-open-file (out (merge-pathnames
                          (format nil "src/sbcl-~A/customize-target-features.lisp"
                                  (getf argv :version)) (homedir))
                         :direction :output :if-exists :supersede :if-does-not-exist :create)
      (format out "~s"
              `(lambda (list)
                 (dolist (i '((:sb-thread ,(get-opt "thread"))
                              (:sb-core-compression ,(get-opt "core-compression"))
                              (:sb-ldb ,(get-opt "ldb"))
                              (:sb-xref-for-internals ,(get-opt "xref-for-internals"))))
                   (if (second i)
                       (pushnew (first i) list)
                       (setf list (remove (first i) list))))
                 list)))
    (cons t argv))
  
  (defun sbcl-make (argv)
    (with-open-file (out (ensure-directories-exist
                          (merge-pathnames (format nil "impls/log/~A-~A/make.log"
                                                   (getf argv :target) (get-opt "as"))
                                           (homedir)))
                         :direction :output :if-exists :append :if-does-not-exist :create)
      (format out "~&--~&~A~%" (date))
      (let* ((src (get-opt "src"))
             (compiler (format nil "~A lisp=~A --no-rc run --" *ros-path* (get-opt "sbcl.compiler")))
             (cmd (format nil "sh make.sh \"--xc-host=~A\" \"--prefix=~A\"" compiler (get-opt "prefix")))
  