anchor.diff:  
     # Help CMake find SDL_mixer.h
     NIX_CFLAGS_COMPILE = "-I${SDL2_mixer}/include/SDL2";
  +
  +  # Create "ivan.desktop" file
  +  ivanDesktop = makeDesktopItem {
  +    name = pname;
  +    exec = pname;
  +    icon = "ivan.png";
  +    desktopName = "IVAN";
  +    genericName = pname;
  +    categories = "Game;AdventureGame;RolePlaying;";
  +    comment = meta.description;
  +  };
  +
  +  # Create appropriate directories. Convert "Icon.bmp" to "ivan.png", then copy
  +  # it and "ivan.desktop" to these directories.
  +  postInstall = ''
  +    mkdir -p $out/share/applications
  +    mkdir -p $out/share/icons/hicolor/32x32/apps
  +    gm convert $src/Graphics/Icon.bmp $out/share/icons/hicolor/32x32/apps/ivan.png
  +    cp ${ivanDesktop}/share/applications/* $out/share/applications
  +  '';
   
     meta = with stdenv.lib; {
       description = "Graphical roguelike game";
  
positive.code: { stdenv, fetchFromGitHub, cmake, pkgconfig, SDL2, SDL2_mixer, alsaLib, libpng, pcre }:
  
  stdenv.mkDerivation rec {
  
  
negative.code:     sha256 = "0mavmwikfsyr5sp65sl8dqknl1yz7c7ds53y1qkma24vsikz3k64";
    };
  
    nativeBuildInputs = [ cmake pkgconfig graphicsmagick ];
  
    buildInputs = [ SDL2 SDL2_mixer alsaLib libpng pcre ];
  
  