--- a/b2g/app.mozbuild
+++ b/b2g/app.mozbuild
@@ -1,16 +1,14 @@
 # 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 not CONFIG['LIBXUL_SDK']:
-    app_libxul_dirs = []
-
     include('/toolkit/toolkit.mozbuild')
 elif CONFIG['ENABLE_TESTS']:
     add_tier_dir('testharness', 'testing/mochitest')
 
 if CONFIG['MOZ_EXTENSIONS']:
     add_tier_dir('app', 'extensions')
 
 add_tier_dir('app', CONFIG['MOZ_BRANDING_DIRECTORY'])

--- a/b2g/dev/app.mozbuild
+++ b/b2g/dev/app.mozbuild
@@ -1,15 +1,14 @@
 # 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 not CONFIG['LIBXUL_SDK']:
-    app_libxul_dirs = []
     include('/toolkit/toolkit.mozbuild')
 
 if CONFIG['MOZ_EXTENSIONS']:
     add_tier_dir('app', 'extensions')
 
 add_tier_dir('app', [CONFIG['MOZ_BRANDING_DIRECTORY']])
 
 if CONFIG['MOZ_WEBAPP_RUNTIME']:

--- a/browser/app.mozbuild
+++ b/browser/app.mozbuild
@@ -1,15 +1,14 @@
 # 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 not CONFIG['LIBXUL_SDK']:
-    app_libxul_dirs = []
     include('/toolkit/toolkit.mozbuild')
 
 if CONFIG['MOZ_EXTENSIONS']:
     add_tier_dir('app', 'extensions')
 
 add_tier_dir('app', [CONFIG['MOZ_BRANDING_DIRECTORY']])
 
 if CONFIG['MOZ_WEBAPP_RUNTIME']:

--- a/mobile/android/app.mozbuild
+++ b/mobile/android/app.mozbuild
@@ -1,16 +1,14 @@
 # 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 not CONFIG['LIBXUL_SDK']:
-    app_libxul_dirs = ['mobile/android/components/build']
-
     include('/toolkit/toolkit.mozbuild')
 
 elif CONFIG['ENABLE_TESTS']:
     add_tier_dir('testharness', 'testing/mochitest')
 
 if CONFIG['MOZ_EXTENSIONS']:
     add_tier_dir('app', 'extensions')
 

--- a/mobile/android/components/moz.build
+++ b/mobile/android/components/moz.build
@@ -36,8 +36,10 @@ EXTRA_PP_COMPONENTS += [
     'DirectoryProvider.js',
     'HelperAppDialog.js',
     'MobileComponents.manifest',
     'SessionStore.js',
     'Sidebar.js',
 ]
 
 DEFINES['ANDROID_PACKAGE_NAME'] = CONFIG['ANDROID_PACKAGE_NAME']
+
+DIRS += ['build']

--- a/toolkit/toolkit.mozbuild
+++ b/toolkit/toolkit.mozbuild
@@ -148,20 +148,16 @@ if CONFIG['MOZ_PREF_EXTENSIONS']:
 add_tier_dir('platform', 'services')
 add_tier_dir('platform', 'startupcache')
 add_tier_dir('platform', 'js/ductwork/debugger')
 add_tier_dir('platform', 'other-licenses/snappy')
 
 if CONFIG['MOZ_GIO_COMPONENT']:
     add_tier_dir('platform', 'extensions/gio')
 
-# Applications can cheat and ask for code to be
-# built before libxul so it can be linked into libxul.
-add_tier_dir('platform', app_libxul_dirs)
-
 add_tier_dir('platform', 'toolkit/library/StaticXULComponentsEnd')
 add_tier_dir('platform', 'toolkit/library')
 
 if CONFIG['MOZ_REPLACE_MALLOC']:
     add_tier_dir('platform', 'memory/replace')
 
 if CONFIG['NS_TRACE_MALLOC']:
     add_tier_dir('platform', 'tools/trace-malloc')

--- a/xulrunner/app.mozbuild
+++ b/xulrunner/app.mozbuild
@@ -1,14 +1,13 @@
 # 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/.
 
-app_libxul_dirs = []
 include('/toolkit/toolkit.mozbuild')
 
 if CONFIG['MOZ_EXTENSIONS']:
     add_tier_dir('app', 'extensions')
 
 if CONFIG['OS_ARCH'] == 'WINNT' and (CONFIG['ENABLE_TESTS'] or
         CONFIG['MOZILLA_OFFICIAL']):
     add_tier_dir('app', 'embedding/tests/winEmbed')