anchor.diff:                 (or #-win32 :interactive nil) nil))
   
   (defun core-extention (&optional (impl (opt "impl")))
  +  "Interface to the roswell C binary. Returns \"core\" on sbcl."
     (roswell:roswell `("roswell-internal-use" "core-extention" ,impl) :string t))
   
   (defun config (c)
  +   "Interface to roswell C binary."
     (let ((result (roswell:roswell `("config" "show" ,c) :string t)))
       (unless (zerop (length result)) result)))
   
   (defun (setf config) (val item)
  +   "Interface to roswell C binary."
     (roswell:roswell (if val
                          `("config" "set" ,item ,val)  ;; set
                          `("config" ,item)) :string t) ;; unset
  
positive.code:                    output nil))
  
  (defun expand (archive dest &key verbose)
    #+win32
    (progn
      (roswell:include "install+7zip")
  
negative.code:      finally (return (coerce r 'string))))
  
  (defun download (uri file &key proxy (verbose nil) (output :interactive))
    "Interface to curl4 in the roswell C binary"
    (declare (ignorable proxy))
    (ensure-directories-exist file)
    (roswell:roswell `("roswell-internal-use" "download" ,(backslash-encode uri)
  