SCL support (thanks to Douglas Crosher). Includes support for

implementations where URIs are valid namestrings, and a mode
        where normal streams are used instead of xstreams and ystreams
        (albeit both SCL-specific at this point).

xml/package.lisp

@@ -6,7 +6,7 @@
 (in-package :cl-user)
 
 (defpackage :cxml
-  (:use :cl :runes :runes-encoding :trivial-gray-streams)
+  (:use :cl :runes :runes-encoding #-scl :trivial-gray-streams)
   (:export
    ;; xstreams
    #:make-xstream