xfce.xfce4-icon-theme: add missing parent icon themes

Also:
- replace gtk2 by gtk3
- intltool and gtk are native build dependences

pkgs/desktops/xfce/art/xfce4-icon-theme.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, pkgconfig, intltool, gtk3, xfce }:
+{ stdenv, fetchurl, pkgconfig, intltool, gtk3, gnome-icon-theme, tango-icon-theme, hicolor-icon-theme, xfce }:
 
 let
   category = "art";
@@ -19,6 +19,15 @@ stdenv.mkDerivation rec {
     gtk3
   ];
 
+  buildInputs = [
+    gnome-icon-theme
+    tango-icon-theme
+    hicolor-icon-theme
+    # missing parent icon theme Industrial
+  ];
+
+  dontDropIconThemeCache = true;
+
   passthru.updateScript = xfce.updateScript {
     inherit pname version;
     attrPath = "xfce.${pname}";