gnu: Add mg.

[taylanbayirli@gmail.com ("Taylan Ulrich Bayırlı/Kammer")]

I'm unsure about the ways I use `substitute*' to patch the Makefile.in
of this (both in the source declaration and in the pre-configure
phase); maybe someone can give me hints on more robust (future proof)
patterns.

===File /home/tub/media/src/guix/0001-gnu-Add-mg.patch======
From f5ee84666973c988633545e58ee84b6fa624862c Mon Sep 17 00:00:00 2001
From: Taylan Ulrich B <taylanbayirli@gmail.com>
Date: Wed, 26 Nov 2014 23:14:16 +0100
Subject: [PATCH] gnu: Add mg.

* gnu/packages/mg.scm: New file.
* gnu-system.am (GNU_SYSTEM_MODULES): Add mg.scm.
---
 gnu-system.am       |  1 +
 gnu/packages/mg.scm | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 gnu/packages/mg.scm

diff --git a/gnu-system.am b/gnu-system.am
index 4c9fcda..77d4915 100644
--- a/gnu-system.am
+++ b/gnu-system.am
@@ -173,6 +173,7 @@ GNU_SYSTEM_MODULES =				\
   gnu/packages/mc.scm				\
   gnu/packages/mcrypt.scm			\
   gnu/packages/messaging.scm			\
+  gnu/packages/mg.scm				\
   gnu/packages/miscfiles.scm			\
   gnu/packages/mit-krb5.scm			\
   gnu/packages/moe.scm				\
diff --git a/gnu/packages/mg.scm b/gnu/packages/mg.scm
new file mode 100644
index 0000000..9906c2c
--- /dev/null
+++ b/gnu/packages/mg.scm
@@ -0,0 +1,71 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014 Taylan Ulrich Bayırlı/Kammer <taylanbayirli@gmail.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 mg)
+  #:use-module (guix licenses)
+  #:use-module (guix download)
+  #:use-module (guix packages)
+  #:use-module (guix build-system gnu)
+  #:use-module (gnu packages ncurses)
+  #:use-module (gnu packages pkg-config))
+
+(define-public mg
+  (package
+    (name "mg")
+    (version "20050429")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append "http://homepage.boetes.org/software/mg/mg-"
+                                  version ".tar.gz"))
+              (sha256
+               (base32
+                "19kib0aha4a40izzds7r63qfb2akq4sily6k28fl0n0zdgq0cna1"))
+              (modules '((guix build utils)))
+              (snippet
+               '(begin
+                  (substitute* "Makefile.in"
+                    (("-Werror") "")
+                    (("-lcurses") "-lncurses")
+                    (("/usr/bin/install" install)
+                     (string-append install " -D")))))))
+    (build-system gnu-build-system)
+    (inputs
+     `(("ncurses" ,ncurses)))
+    (arguments
+     ;; No test suite available.
+     '(#:tests? #f
+       #:phases (alist-cons-before
+                 'configure 'pre-configure
+                 (lambda* (#:key inputs outputs #:allow-other-keys)
+                   ;; Fix pathes in Makefile.in.
+                   (substitute* "Makefile.in"
+                     (("(prefix=[[:blank:]]*)/usr/local" all prefix)
+                      (string-append prefix (assoc-ref outputs "out")))
+                     (("/usr/bin/install")
+                      (string-append (assoc-ref inputs "coreutils")
+                                     "/bin/install"))
+                     (("/usr/bin/strip")
+                      (string-append (assoc-ref inputs "binutils")
+                                     "/bin/strip"))))
+                 %standard-phases)))
+    (home-page "http://homepage.boetes.org/software/mg/")
+    (synopsis "Microscopic GNU Emacs clone")
+    (description
+     "mg is Micro GNU Emacs; this is a portable version of the mg maintained
+by the OpenBSD team.")
+    (license public-domain)))
-- 
2.1.2

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