anchor.diff:                    gcr libsecret pulseaudio gnome3.yelp_xsl gdk_pixbuf
                     libnotify clutter libsoup gnutls libgee p11_kit
                     libcanberra_gtk3 telepathy_farstream farstream
  +                  gnome3.gnome_icon_theme hicolor_icon_theme gnome3.gnome_icon_theme_symbolic
                     gnome3.gsettings_desktop_schemas file libtool librsvg ];
   
     NIX_CFLAGS_COMPILE = [ "-I${dbus_glib}/include/dbus-1.0"
  
positive.code:     for f in $out/bin/* $out/libexec/*; do
        wrapProgram $f \
          --set GDK_PIXBUF_MODULE_FILE "$GDK_PIXBUF_MODULE_FILE" \
          --prefix XDG_DATA_DIRS : "$XDG_ICON_DIRS:${gnome3.gnome_themes_standard}/:${gnome3.gnome_themes_standard}/share:${hicolor_icon_theme}/share:$out/share:$GSETTINGS_SCHEMAS_PATH"
      done
      rm $out/share/icons/hicolor/icon-theme.cache
    '';
  
negative.code:   };
  
    propagatedUserEnvPkgs = [ gnome3.gnome_themes_standard
                              gnome_online_accounts shared_mime_info ];
    propagatedBuildInputs = [ folks telepathy_logger evolution_data_server
                              telepathy_mission_control ];
    buildInputs = [ pkgconfig gtk3 glib webkitgtk intltool itstool
  