anchor.diff:      substituteInPlace src/redshift-gtk/redshift-gtk \
         --replace "/usr/bin/env python3" "${python}/bin/${python.executable}"
     '';
  -
     postInstall = stdenv.lib.optionalString guiSupport ''
       wrapProgram "$out/bin/redshift-gtk" \
  +      --set GDK_PIXBUF_MODULE_FILE "$GDK_PIXBUF_MODULE_FILE" \
         --prefix PYTHONPATH : "$PYTHONPATH" \
         --prefix GI_TYPELIB_PATH : "$GI_TYPELIB_PATH" \
         --prefix XDG_DATA_DIRS : "$out/share:${hicolor_icon_theme}/share"
  
positive.code: { fetchurl, stdenv, gettext, intltool, makeWrapper, pkgconfig
  , geoclue2
  , guiSupport ? true, hicolor_icon_theme, gtk3, python, pygobject3, pyxdg
  , drmSupport ? true, libdrm
  , randrSupport ? true, libxcb
  , vidModeSupport ? true, libX11, libXxf86vm
  
negative.code:   };
  
    buildInputs = [ geoclue2 ]
      ++ stdenv.lib.optionals guiSupport [ hicolor_icon_theme librsvg gtk3
        python pygobject3 pyxdg ]
      ++ stdenv.lib.optionals drmSupport [ libdrm ]
      ++ stdenv.lib.optionals randrSupport [ libxcb ]
      ++ stdenv.lib.optionals vidModeSupport [ libX11 libXxf86vm ];
  