anchor.diff:      gdk_pixbuf
       glib
       gnome2.GConf
  -    gtk2
  +    gtk3
       pango
       libX11
       libXScrnSaver
  
positive.code: in
    stdenv.mkDerivation rec {
      name = "mattermost-desktop-${version}";
      version = "4.1.2";
  
      src =
        if stdenv.hostPlatform.system == "x86_64-linux" then
          fetchurl {
            url = "https://releases.mattermost.com/desktop/${version}/${name}-linux-x64.tar.gz";
            sha256 = "16dn6870bs1nfl2082ym9gwvmqb3i5sli48qprap80p7riph6k9s";
          }
        else if stdenv.hostPlatform.system == "i686-linux" then
          fetchurl {
            url = "https://releases.mattermost.com/desktop/${version}/${name}-linux-ia32.tar.gz";
            sha256 = "145zb1l37fa2slfrrlprlwzcc5km3plxs374yhgix25mlg2afkqr";
          }
        else
          throw "Mattermost-Desktop is not currently supported on ${stdenv.hostPlatform.system}";
  
negative.code: { stdenv, lib, fetchurl, gnome2, gtk3, pango, atk, cairo, gdk_pixbuf, glib,
  freetype, fontconfig, dbus, libX11, xorg, libXi, libXcursor, libXdamage,
  libXrandr, libXcomposite, libXext, libXfixes, libXrender, libXtst,
  libXScrnSaver, nss, nspr, alsaLib, cups, expat, udev }:
  