anchor.diff:  { lib
   , stdenv
  -, fetchgit
  +, fetchFromGitHub
   , xorgproto
   , libX11
   , libXft
  
positive.code:     libXinerama
      libjpeg
      giflib
      pkg-config
    ];
  in
  stdenv.mkDerivation rec {
    version = "unstable-2015-03-01";
    pname = "skippy-xd";
    inherit buildInputs;
    src = fetchgit {
      url = "https://github.com/richardgv/skippy-xd/";
      rev = "397216ca67";
      sha256 = "0zcjacilmsv69rv85j6nfr6pxy8z36w1sjz0dbjg6s5m4kga1zl8";
    };
    makeFlags = [ "PREFIX=$(out)" ];
    preInstall = ''
      sed -e "s@/etc/xdg@$out&@" -i Makefile
    '';
    meta = {
      description = "Expose-style compositing-based standalone window switcher";
      license = lib.licenses.gpl2Plus;
      maintainers = [ lib.maintainers.raskin ];
      platforms = lib.platforms.linux;
    };
  }
  
negative.code: , giflib
  , pkg-config
  }:
  stdenv.mkDerivation rec {
    pname = "skippy-xd";
    version = "unstable-2015-03-01";
    src = fetchFromGitHub {
      owner = "richardgv";
      repo = "skippy-xd";
      rev = "397216ca67074c71314f5e9a6e3f1710ccabc29e";
      sha256 = "sha256-iP6g3iS1aPPkauBLHbgZH/l+TXbWyIJ2TmbrSiNTkn0=";
    };
    nativeBuildInputs = [ pkg-config ];
    buildInputs = [
      xorgproto
      libX11
  