gtk: reorganize

This directory was mess of patches and hooks.
Have a patches dir and a setup-hooks dir.

pkgs/development/libraries/gtk/2.x.nix

@@ -26,21 +26,21 @@ stdenv.mkDerivation rec {
   enableParallelBuilding = true;
 
   setupHooks =  [
-    ./gtk2-clean-immodules-cache.sh
-    ./drop-icon-theme-cache.sh
+    ./hooks/gtk2-clean-immodules-cache.sh
+    ./hooks/drop-icon-theme-cache.sh
   ];
 
   nativeBuildInputs = [ setupHooks perl pkgconfig gettext gobject-introspection ];
 
   patches = [
-    ./2.0-immodules.cache.patch
-    ./gtk2-theme-paths.patch
+    ./patches/2.0-immodules.cache.patch
+    ./patches/gtk2-theme-paths.patch
   ] ++ optionals stdenv.isDarwin [
     (fetchpatch {
       url = https://bug557780.bugzilla-attachments.gnome.org/attachment.cgi?id=306776;
       sha256 = "0sp8f1r5c4j2nlnbqgv7s7nxa4cfwigvm033hvhb1ld652pjag4r";
     })
-    ./2.0-darwin-x11.patch
+    ./patches/2.0-darwin-x11.patch
   ];
 
   propagatedBuildInputs = with xorg;