anchor.diff:  (defun project-website (project)
     (or (primary-system-website project)
         (guess-website project)
  -      (cliki-link project)))
  +      (cliki-link project)
  +      (error "Can't determine project website for ~S" project)))
   
   (defun github-properties (url)
     (ppcre:register-groups-bind (user repo)
  
positive.code: 
  (defparameter *guess-website-patterns*
    '(("//github.com/(.*)\\.git" "https://github.com/" 0 "/")
      ("(https://gitlab.common-lisp.net/.*)\.git$")
      ("(https://gitlab.com/.*)\.git$")
      ("//mr.gy/(.*?)/(.*?)/" "http://mr.gy/" 0 "/" 1 "/")
      ("(http://(.*?).googlecode.com/)" 0)
      ("//common-lisp.net/projects/(.*?)/" "http://common-lisp.net/projects/" 0)
  
negative.code:       (let ((substitution (substitute-if-matches regex
                                                   location
                                                   substitution)))
          (when (and substitution (not (equal substitution "")))
            (return substitution))))))
  
  (defun guess-website (project)
  