--- a/toolkit/toolkit.mozbuild
+++ b/toolkit/toolkit.mozbuild
@@ -1,14 +1,19 @@
 # -*- 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/.
 
+DIRS += [
+    '/toolkit/library/gtest/rust',
+    '/toolkit/library/rust',
+]
+
 if CONFIG['MOZ_SANDBOX']:
     DIRS += ['/security/sandbox']
 
 DIRS += [
     # Depends on NSS and NSPR, and must be built after sandbox or else B2G emulator
     # builds fail.
     '/security/certverifier',
     # Depends on certverifier
@@ -129,18 +134,16 @@ DIRS += [
 ]
 
 if CONFIG['MOZ_PREF_EXTENSIONS']:
     DIRS += ['/extensions/pref']
 
 DIRS += [
     '/devtools',
     '/toolkit/library',
-    '/toolkit/library/gtest/rust',
-    '/toolkit/library/rust',
     '/toolkit/library/StaticXULComponentsEnd',
     '/services',
     '/startupcache',
     '/js/ductwork/debugger',
     '/other-licenses/snappy',
 ]
 
 if 'gtk' in CONFIG['MOZ_WIDGET_TOOLKIT']: