anchor.diff:  
       gnome3.gconf
       gdk_pixbuf
  -    gtk2
  -
  +    gtk3
   
       gnome3.gnome-keyring
   
  
positive.code:     if stdenv.system == "x86_64-linux" then
        fetchurl {
          url = "https://repo.skype.com/deb/pool/main/s/skypeforlinux/skypeforlinux_${version}_amd64.deb";
          sha256 = "193icz1s385d25qzm5vx58h66m4hfwwmkavn0p3w6631gj617hig";
        }
      else
        throw "Skype for linux is not supported on ${stdenv.system}";
  
negative.code: { stdenv, fetchurl, dpkg, makeWrapper
  , alsaLib, atk, cairo, cups, curl, dbus, expat, fontconfig, freetype, gdk_pixbuf, glib, glibc, gnome3
  , gtk3, libnotify, libpulseaudio, libsecret, libv4l, nspr, nss, pango, systemd, xorg }:
  
  let
  
    # Please keep the version x.y.0.z and do not update to x.y.76.z because the
    # source of the latter disappears much faster.
    version = "8.24.0.2";
  
    rpath = stdenv.lib.makeLibraryPath [
      alsaLib
  