anchor.diff:      glib
       gnome2.GConf
       gnome2.gdk_pixbuf
  -    gnome2.gtk
  +    gnome3.gtk
       gnome2.pango
       libnotify
       libxcb
  
positive.code: { stdenv, fetchurl, dpkg
  , alsaLib, atk, cairo, cups, curl, dbus, expat, fontconfig, freetype, glib
  , gnome2, libnotify, libxcb, nspr, nss, systemd, xorg }:
  
  let
  
    version = "1.13.1";
  
    rpath = stdenv.lib.makeLibraryPath [
      alsaLib
  
negative.code:     if stdenv.hostPlatform.system == "x86_64-linux" then
        fetchurl {
          url = "https://downloads.mongodb.com/compass/mongodb-compass_${version}_amd64.deb";
          sha256 = "085xq1ik8kyza1kq9kn0pf98zk6g2qa21clxhn48rgnqk20aninv";
        }
      else
        throw "MongoDB compass is not supported on ${stdenv.hostPlatform.system}";
  