Atari800: no more ROM install

Now, the expression will not install ROM files anymore. It is easier the
final user install them locally by himself, in a local directory.
Also, it appears that there is a missing ROM in the package provided by
the project's site.

pkgs/misc/emulators/atari800/builder.sh

@@ -1,13 +0,0 @@
-source $stdenv/setup
-
-preConfigure() {
-    cd src
-}
-
-postInstall() {
-    romsDir=$out/share/atari800/roms
-    mkdir -p $romsDir
-    unzip $rom -d $romsDir
-}
-
-genericBuild

pkgs/misc/emulators/atari800/default.nix

@@ -5,22 +5,18 @@ with stdenv.lib;
 stdenv.mkDerivation rec{
   name = "atari800-${version}";
   version = "3.1.0";
-  builder = ./builder.sh;
 
   src = fetchurl {
     url = "mirror://sourceforge/atari800/atari800/${version}/${name}.tar.gz";
     sha256 = "030yz5l1wyq9l0dmiimiiwpzrjr43whycd409xhhpnrdx76046wh";
   };
 
-  rom = fetchurl {
-    url = http://downloads.sourceforge.net/project/atari800/ROM/Original%20XL%20ROM/xf25.zip;
-    sha256 = "12jbawxs04i0wm3910n7f3phsybdp8nndxc0xlsnzp8k0k8hmblq";
-  };
-
   buildInputs = [ unzip zlib SDL readline mesa libX11 ];
 
   configureFlags = "--target=default --with-video=sdl --with-sound=sdl --with-readline --with-opengl --with-x --enable-riodevice";
 
+  preConfigure = "cd src";
+
   meta = {
     homepage = "http://atari800.sourceforge.net/";
     description = "An Atari 8-bit emulator";