gnu: Add c-ares.

* gnu/packages/aria2.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.

gnu-system.am

@@ -35,6 +35,7 @@ GNU_SYSTEM_MODULES =				\
   gnu/packages/aidc.scm				\
   gnu/packages/apl.scm				\
   gnu/packages/apr.scm				\
+  gnu/packages/aria2.scm			\
   gnu/packages/asciidoc.scm			\
   gnu/packages/aspell.scm			\
   gnu/packages/attr.scm				\

gnu/packages/aria2.scm

@@ -0,0 +1,49 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 Efraim Flashner <efraim@flashner.co.il>
+;;;
+;;; 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 aria2)
+  #:use-module ((guix licenses) #:prefix license:)
+  #:use-module (guix download)
+  #:use-module (guix packages)
+  #:use-module (guix build-system gnu)
+  #:use-module (gnu packages pkg-config))
+
+(define-public c-ares
+  (package
+    (name "c-ares")
+    (version "1.10.0")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append
+                    "http://c-ares.haxx.se/download/" name "-" version
+                    ".tar.gz"))
+              (sha256
+               (base32
+                "1nyka87yf2jfd0y6sspll0yxwb8zi7kyvajrdbjmh4axc5s1cw1x"))))
+    (build-system gnu-build-system)
+    (native-inputs
+     `(("pkg-config" ,pkg-config)))
+    (home-page "http://c-ares.haxx.se/")
+    (synopsis "C library for asynchronous DNS requests")
+    (description
+      "C-ares is a C library that performs DNS requests and name resolution
+asynchronously.  It is intended for applications which need to perform DNS
+queries without blocking, or need to perform multiple DNS queries in parallel.
+The primary examples of such applications are servers which communicate with
+multiple clients and programs with graphical user interfaces.")
+    (license (license:x11-style "http://c-ares.haxx.se/license.html"))))