anchor.diff: -{ fetchurl, stdenv, pkgconfig, gnome3, python, dconf
  +{ fetchurl, stdenv, pkgconfig, gnome3, python3, dconf
   , intltool, libsoup, libxml2, libsecret, icu, sqlite
   , p11_kit, db, nspr, nss, libical, gperf, makeWrapper, valaSupport ? true
   , vala, cmake, kerberos, openldap, webkitgtk, libaccounts-glib, json_glib }:
  
positive.code:   '';
  
    meta = with stdenv.lib; {
      platforms = platforms.linux;
      maintainers = gnome3.maintainers;
    };
  
  }
  
negative.code: stdenv.mkDerivation rec {
    inherit (import ./src.nix fetchurl) name src;
  
    nativeBuildInputs = [
      cmake pkgconfig intltool python3 gperf makeWrapper
    ] ++ stdenv.lib.optional valaSupport vala;
    buildInputs = with gnome3; [
      glib libsoup libxml2 gtk gnome_online_accounts
      gcr p11_kit libgweather libgdata libaccounts-glib json_glib
      icu sqlite kerberos openldap webkitgtk
    ];
  
    propagatedBuildInputs = [ libsecret nss nspr libical db ];
  
    # uoa irrelevant for now
    cmakeFlags = [
      "-DENABLE_UOA=OFF"
    ] ++ stdenv.lib.optionals valaSupport [
      "-DENABLE_VALA_BINDINGS=ON"
      "-DENABLE_INTROSPECTION=ON"
      "-DCMAKE_SKIP_BUILD_RPATH=OFF"
    ];
  
    enableParallelBuilding = true;
  
  