gnu: Add tre (including the agrep utility)

* gnu/packages/tre.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.

gnu-system.am

@@ -251,6 +251,7 @@ GNU_SYSTEM_MODULES =				\
   gnu/packages/time.scm				\
   gnu/packages/tmux.scm				\
   gnu/packages/tor.scm				\
+  gnu/packages/tre.scm				\
   gnu/packages/unclutter.scm			\
   gnu/packages/unrtf.scm			\
   gnu/packages/upnp.scm				\

gnu/packages/tre.scm

@@ -0,0 +1,45 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright 2014 John Darrington
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu packages tre)
+  #:use-module (gnu packages)
+  #:use-module (guix packages)
+  #:use-module (guix download)
+  #:use-module (guix build-system gnu)
+  #:use-module (guix licenses))
+
+(define-public tre
+  (package
+    (name "tre")
+    (version "0.8.0")
+    (source
+      (origin
+        (method url-fetch)
+        (uri       
+          (string-append "http://laurikari.net/tre/" name "-" version
+                         ".tar.bz2"))
+        (sha256
+          (base32 "0n36cgqys59r2gmb7jzbqiwsy790v8nbxk82d2n2saz0rp145ild"))))
+
+    (build-system gnu-build-system)
+    (synopsis "Approximate regex matching library and agrep utility")
+    (description "Superset of the POSIX regex API, enabling approximate
+matching.  Also ships a version of the agrep utility which behaves similar to
+grep but features ineaxct matching.")
+    (home-page "http://laurikari.net/tre")
+    (license bsd-2)))