gnu: Add dgen.

* nongnu/packages/emulators.scm: New file.
(dgen): New variable.

nongnu/packages/emulators.scm

@@ -0,0 +1,45 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2019 Pierre Neidhardt <mail@ambrevar.xyz>
+;;;
+;;; This file is not 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-public dgen
+  (package
+    (name "dgen")
+    (version "1.33")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append
+             "mirror://sourceforge/dgen/dgen/"
+             version "/dgen-sdl-" version ".tar.gz"))
+       (sha256
+        (base32
+         "07pnvsw04jq9pdiwfhp0nr728rwqq2y6w648gz3p6a622xhc1qlr"))))
+    (build-system gnu-build-system)
+    (inputs
+     `(("sdl" ,sdl)
+       ("libarchive" ,libarchive)
+       ("libgl" ,mesa)))
+    (home-page "http://dgen.sourceforge.net")
+    (synopsis "Emulator for Sega Genesis/Mega Drive systems")
+    (description
+     "DGen isn't the best Mega Drive/Genesis emulator out there, but it works
+and it's probably the most portable.  It's one of the few that's x86_64
+compatible.  It's also perfect for command line freaks.")
+    (license (list license:bsd-3
+                   ;; Many non-free licenses.
+                   (nonfree "https://sourceforge.net/p/dgen/dgen/ci/master/tree/COPYING")))))