anchor.diff:      "--disable-gtk-doc-html"
       "--disable-gtk-doc-pdf"
       (enFlag "introspection" (gobject-introspection != null) null)
  +    (enFlag "vala" (vala != null) null)
  +    (enFlag "telepathy" (telepathy_glib != null) null)
       "--enable-backend"
       "--disable-inspector"
       "--enable-exchange"
  
positive.code:     rest
      pango
      telepathy_glib
      webkitgtk
      xorg.libX11
    ];
  
    configureFlags = [
      "--disable-maintainer-mode"
      "--enable-schemas-compile"
      "--enable-compile-warnings"
      "--disable-iso-c"
  
negative.code: 
  stdenv.mkDerivation rec {
    name = "gnome-online-accounts-${version}";
    versionMajor = "3.20";
    versionMinor = "0";
    version = "${versionMajor}.${versionMinor}";
  
    src = fetchurl {
      url = "mirror://gnome/sources/gnome-online-accounts/${versionMajor}/${name}.tar.xz";
      sha256 = "c98233914c455dc21f8c73904dd2881bee6bfa117a5bdc573ba3a8550c36a460";
    };
  
    nativeBuildInputs = [
  