diff -r 000000000000 -r 6474c204b198 dom/xbl/builtin/moz.build
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/xbl/builtin/moz.build	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+if CONFIG['OS_ARCH'] == 'WINNT':
+    DIRS += ['win']
+elif CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
+    DIRS += ['mac']
+elif CONFIG['MOZ_WIDGET_TOOLKIT'] == 'android':
+    DIRS += ['android']
+elif CONFIG['MOZ_WIDGET_TOOLKIT'] in ('qt', 'gtk2', 'gtk3'):
+    DIRS += ['unix']
+else:
+    DIRS += ['emacs']
+