anchor.diff:  
       mkdir -p $out/share/applications
       ln -s ${desktopItem}/share/applications/* $out/share/applications/
  +
  +    ${openjdk}/bin/jar xf $out/minecraft.jar favicon.png
  +    install -D favicon.png $out/share/icons/hicolor/32x32/apps/minecraft.png
     '';
   
     meta = {
  
positive.code: assert useAlsa -> alsaOss != null;
  
  let
    icon = fetchurl {
      url = "https://hydra-media.cursecdn.com/minecraft.gamepedia.com/c/c5/Grass.png";
      sha256 = "438c0f63e379e92af1b5b2e06cc5e3365ee272810af65ebc102304bce4fa8c4b";
    };
  
    desktopItem = makeDesktopItem {
      name = "minecraft";
      exec = "minecraft";
      icon = "${icon}";
      comment = "A sandbox-building game";
      desktopName = "Minecraft";
      genericName = "minecraft";
  
negative.code: { stdenv, fetchurl, makeDesktopItem
  , jre, libX11, libXext, libXcursor, libXrandr, libXxf86vm
  , openjdk
  , mesa, openal
  , useAlsa ? false, alsaOss ? null }:
  with stdenv.lib;
  