Add odamex, a client/server multiplayer doom port

note that odalaunch is not included in this package, users are
expected to use doomseeker. If you would like an option for
odalaunch, please bother me(MP2E)

pkgs/games/odamex/default.nix

@@ -0,0 +1,24 @@
+{ stdenv, cmake, fetchurl, pkgconfig, SDL, SDL_mixer, SDL_net }:
+
+stdenv.mkDerivation rec {
+  name = "odamex-0.7.0";
+  src = fetchurl {
+    url = http://downloads.sourceforge.net/odamex/odamex-src-0.7.0.tar.bz2;
+    sha256 = "0cb6p58yv55kdyfj7s9n9xcwpvxrj8nyc6brw9jvwlc5n4y3cd5a";
+  };
+
+  cmakeFlags = ''
+    -DCMAKE_BUILD_TYPE=Release
+  '';
+
+  buildInputs = [ cmake pkgconfig SDL SDL_mixer SDL_net ];
+
+  enableParallelBuilding = true;
+
+  meta = {
+    homepage = http://odamex.net/;
+    description = "A client/server port for playing old-school Doom online";
+    license = stdenv.lib.licenses.gpl2;
+    maintainers = with stdenv.lib.maintainers; [ MP2E ];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -1869,6 +1869,8 @@ let
 
   odt2txt = callPackage ../tools/text/odt2txt { };
 
+  odamex = callPackage ../games/odamex { };
+
   offlineimap = callPackage ../tools/networking/offlineimap {
     inherit (pythonPackages) sqlite3;
   };