gnu: texinfo: Add version 6.0.

* gnu/packages/texinfo.scm (texinfo-6): New variable.

gnu/packages/texinfo.scm

 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012, 2013, 2015 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2014 Eric Bavier <bavier@member.fsf.org>
 ;;;
 ;;; This file is part of GNU Guix.
@@ -53,6 +53,18 @@ (define-public texinfo
 is on expressing the content semantically, avoiding physical markup commands.")
     (license gpl3+)))
 
+(define-public texinfo-6
+  (package
+    (inherit texinfo)
+    (version "6.0")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append "mirror://gnu/texinfo/texinfo-"
+                                  version ".tar.xz"))
+              (sha256
+               (base32
+                "1r3i6jyynn6ab45fxw5bms8mflk9ry4qpj6gqyry72vfd5c47fhi"))))))
+
 (define-public texinfo-4
   (package (inherit texinfo)
     (version "4.13a")