relax base dependency to <5

xhtml.cabal

 Name:               xhtml
-Version:            3000.2.0.4
+Version:            3000.2.0.5
 Copyright:          Bjorn Bringert 2004-2006, Andy Gill and the Oregon
                     Graduate Institute of Science and Technology, 1999-2001
 Maintainer:         Chris Dornan <chris@chrisdornan.com>
@@ -21,7 +21,7 @@ Source-repository head
     location:       git@github.com:haskell/xhtml.git
 
 library 
-    Build-depends:  base >= 4.0 && < 4.6
+    Build-depends:  base >= 4.0 && < 5.0
     Exposed-modules: 
                     Text.XHtml, 
                     Text.XHtml.Frameset,