gnu: Introduce (gnu artwork) module.

* gnu/artwork.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add it.
* gnu/services/xorg.scm: Use it.
  (%artwork-repository): Remove.
* gnu/system/grub.scm: Use it.
  (%artwork-repository): Remove.

gnu-system.am

@@ -23,6 +23,7 @@
 
 GNU_SYSTEM_MODULES =				\
   gnu.scm					\
+  gnu/artwork.scm				\
   gnu/packages.scm				\
   gnu/packages/abiword.scm			\
   gnu/packages/acct.scm				\

gnu/artwork.scm

@@ -0,0 +1,40 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014 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 artwork)
+  #:use-module (guix packages)
+  #:use-module (guix git-download)
+  #:export (%artwork-repository))
+
+;;; Commentary:
+;;;
+;;; Common place for the definition of the Guix artwork repository.
+;;;
+;;; Code:
+
+(define %artwork-repository
+  (origin
+    (method git-fetch)
+    (uri (git-reference
+          (url "git://git.savannah.gnu.org/guix/guix-artwork.git")
+          (commit "71d77b1")))
+    (sha256
+     (base32
+      "03j0fwh6j5knzbfjj3cs0a30cssy706p18b8x7d1p91p29hlzjif"))))
+
+;;; artwork.scm ends here

gnu/services/xorg.scm

@@ -17,8 +17,7 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (gnu services xorg)
-  #:use-module (guix packages)
+  #:use-module (gnu artwork)
-  #:use-module (guix git-download)
   #:use-module (gnu services)
   #:use-module (gnu system linux)                 ; 'pam-service'
   #:use-module ((gnu packages base) #:select (canonical-package))
@@ -162,16 +161,6 @@ EndSection
 ;;; SLiM log-in manager.
 ;;;
 
-(define %artwork-repository
-  (origin
-    (method git-fetch)
-    (uri (git-reference
-          (url "git://git.savannah.gnu.org/guix/guix-artwork.git")
-          (commit "71d77b1")))
-    (sha256
-     (base32
-      "03j0fwh6j5knzbfjj3cs0a30cssy706p18b8x7d1p91p29hlzjif"))))
-
 (define %default-slim-theme
   ;; Theme based on work by Felipe López.
   #~(string-append #$%artwork-repository "/slim"))

gnu/system/grub.scm

@@ -24,7 +24,7 @@
   #:use-module (guix monads)
   #:use-module (guix gexp)
   #:use-module (guix download)
-  #:use-module (guix git-download)
+  #:use-module (gnu artwork)
   #:autoload   (gnu packages grub) (grub)
   #:autoload   (gnu packages inkscape) (inkscape)
   #:autoload   (gnu packages imagemagick) (imagemagick)
@@ -77,16 +77,6 @@
   (color-highlight grub-theme-color-highlight
                    (default '((fg . white) (bg . blue)))))
 
-(define %artwork-repository
-  (origin
-    (method git-fetch)
-    (uri (git-reference
-          (url "git://git.savannah.gnu.org/guix/guix-artwork.git")
-          (commit "281157a")))
-    (sha256
-     (base32
-      "02x1myh013mzqnr28d4k1mxs4malv5vszpxdwkjarbhbbkchypz5"))))
-
 (define %background-image
   (grub-image
    (aspect-ratio 4/3)