anchor.diff:  
     # Still unstable with luajit
     buildInputs = [ lua5_1 zlib sqlite ncurses ]
  -                ++ lib.optionals tileMode [ libpng SDL2 SDL2_image freetype libGLU_combined ];
  +                ++ lib.optionals tileMode [ libpng SDL2 SDL2_image freetype libGLU_combined ]
  +                ++ lib.optional enableSound SDL2_mixer;
   
     preBuild = ''
       cd crawl-ref/source
  
positive.code: 
    makeFlags = [ "prefix=$(out)" "FORCE_CC=cc" "FORCE_CXX=c++" "HOSTCXX=c++"
                  "SAVEDIR=~/.crawl" "sqlite=${sqlite.dev}"
                ] ++ lib.optional tileMode "TILES=y";
  
    postInstall = lib.optionalString tileMode "mv $out/bin/crawl $out/bin/crawl-tiles";
  
  
negative.code: { stdenv, lib, fetchFromGitHub, which, sqlite, lua5_1, perl, zlib, pkgconfig, ncurses
  , dejavu_fonts, libpng, SDL2, SDL2_image, SDL2_mixer, libGLU_combined, freetype, pngcrush, advancecomp
  , tileMode ? false, enableSound ? tileMode
  }:
  
  stdenv.mkDerivation rec {
  