anchor.diff:      sha256 = "1ak32fj5xkk2fvmm3g8i7wzmk4bh2ijsp8fzvvw5wj6365p9j24v";
     };
   
  -  nativeBuildInputs = [ pkgconfig ];
  -  buildInputs = [ SDL libpng xz zlib freetype fontconfig ];
  +  nativeBuildInputs = [ pkgconfig makeWrapper ];
  +  buildInputs = [ SDL libpng xz zlib freetype fontconfig ]
  +    ++ stdenv.lib.optional withFluidSynth [ fluidsynth soundfont-fluid ];
   
     prefixKey = "--prefix-dir=";
   
  
positive.code: { stdenv, fetchurl, fetchzip, pkgconfig, SDL, libpng, zlib, xz, freetype, fontconfig
  , withOpenGFX ? true, withOpenSFX ? true, withOpenMSX ? true
  }:
  
  let
  
negative.code:     sha256 = "0qnmfzz0v8vxrrvxnm7szphrlrlvhkwn3y92b4iy0b4b6yam0yd4";
    };
  
    playmidi = writeScriptBin "playmidi" ''
      #!/bin/sh
      trap "${procps}/bin/pkill fluidsynth" EXIT
      ${fluidsynth}/bin/fluidsynth -a ${audioDriver} -i ${soundfont-fluid}/share/soundfonts/FluidR3_GM2-2.sf2 $*
    '';
  
  in
  stdenv.mkDerivation rec {
    name = "openttd-${version}";
  