gnu: Add libevent.

* gnu/packages/libevent.scm: New file.
* Makefile.am (MODULES): Add it.

Makefile.am

@@ -85,6 +85,7 @@ MODULES =					\
   gnu/packages/indent.scm			\
   gnu/packages/ld-wrapper.scm			\
   gnu/packages/less.scm				\
+  gnu/packages/libevent.scm			\
   gnu/packages/libffi.scm			\
   gnu/packages/libidn.scm			\
   gnu/packages/libjpeg.scm			\

gnu/packages/libevent.scm

@@ -0,0 +1,63 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2013 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; 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 libevent)
+  #:use-module (gnu packages)
+  #:use-module (guix licenses)
+  #:use-module (guix packages)
+  #:use-module (guix download)
+  #:use-module (guix build-system gnu)
+  #:use-module (gnu packages which)
+  #:use-module (gnu packages python))
+
+(define-public libevent
+  (package
+    (name "libevent")
+    (version "2.0.21")
+    (source (origin
+             (method url-fetch)
+             (uri (string-append
+                   "https://github.com/downloads/libevent/libevent/libevent-"
+                   version
+                   "-stable.tar.gz"))
+             (sha256
+              (base32
+               "1xblymln9vihdmf1aqkp8chwvnhpdch3786bh30bj75slnl31992"))))
+    (build-system gnu-build-system)
+    (inputs
+     `(("patch/dns-tests" ,(search-patch "libevent-dns-tests.patch"))
+
+       ;; Dependencies used for the tests and for `event_rpcgen.py'.
+       ("which" ,which)
+       ("python" ,python)))
+    (arguments
+     '(#:patches (list (assoc-ref %build-inputs "patch/dns-tests"))))
+    (home-page "http://libevent.org/")
+    (synopsis
+     "libevent, an event notification library")
+    (description
+     "The libevent API provides a mechanism to execute a callback
+function when a specific event occurs on a file descriptor or after a
+timeout has been reached.  Furthermore, libevent also support callbacks
+due to signals or regular timeouts.
+
+libevent is meant to replace the event loop found in event driven
+network servers.  An application just needs to call event_dispatch() and
+then add or remove events dynamically without having to change the event
+loop.")
+    (license bsd-3)))