diff --git a/cxml.asd b/cxml.asd
index 95921fc..fa834ff 100644
--- a/cxml.asd
+++ b/cxml.asd
@@ -7,13 +7,31 @@
 (defmethod asdf:component-name ((c dummy-cxml-component))
   :cxml)
 
-;; force loading of closure-common.asd, which installs *FEATURES* this
-;; file depends on.  Use MISSING-DEPENDENCY for asdf-install.
-(unless (find-system :closure-common nil)
-  (error 'missing-dependency
-	 :required-by (make-instance 'dummy-cxml-component)
-	 :version nil
-	 :requires :closure-common))
+(progn
+  (format t "~&;;; Checking for wide character support...")
+  (force-output)
+  (flet ((test (code)
+	   (and (< code char-code-limit) (code-char code))))
+    (cond
+      ((not (test 50000))
+       (format t " no, reverting to octet strings.~%")
+       #+rune-is-character
+       (error "conflicting unicode configuration.  Please recompile.")
+       (pushnew :rune-is-integer *features*))
+      ((code-char 70000)
+       (when (test #xD800)
+	 (format t " WARNING: Lisp implementation doesn't use UTF-16, ~
+                     but accepts surrogate code points.~%"))
+       (format t " yes, using code points.~%")
+       #+(or rune-is-integer rune-is-utf-16)
+       (error "conflicting unicode configuration.  Please recompile.")
+       (pushnew :rune-is-character *features*))
+      (t
+       (format t " yes, using UTF-16.~%")
+       #+(or rune-is-integer (and rune-is-character (not rune-is-utf-16)))
+       (error "conflicting unicode configuration.  Please recompile.")
+       (pushnew :rune-is-utf-16 *features*)
+       (pushnew :rune-is-character *features*)))))
 
 (defclass closure-source-file (cl-source-file) ())