--- a/Makefile.in
+++ b/Makefile.in
@@ -78,16 +78,20 @@ include $(topsrcdir)/mozilla/toolkit/moz
 ifeq ($(OS_ARCH),WINNT)
   # PDB files don't get moved to dist, so we need to scan the whole objdir
   MAKE_SYM_STORE_PATH=..
 endif
 
 buildsymbols :: $(SUBMAKEFILES)
 	$(MAKE) -C mozilla MAKE_SYM_STORE_PATH=$(MAKE_SYM_STORE_PATH) SYM_STORE_SOURCE_DIRS="$(topsrcdir)/mozilla/extensions/inspector $(topsrcdir)/ldap/sdks $(topsrcdir)/mozilla $(topsrcdir)" $@
 
+# If we don't specify this, then we will end up trying to build as if we were a
+# regular directory in the build tree.
+SUPPRESS_DEFAULT_RULES := 1
+
 include $(topsrcdir)/config/rules.mk
 
 # defined in (mozilla/.../)package-name.mk
 export MOZ_SOURCE_STAMP
 
 DIST_GARBAGE = config.cache config.log config.status* config-defs.h \
    config/autoconf.mk \
    unallmakefiles \

--- a/bridge/bridge.mozbuild
+++ b/bridge/bridge.mozbuild
@@ -1,18 +1,19 @@
 # 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 += [bridge_reldir + 'mozilla/xpfe/components/autocomplete']
+mailnews_dirs = []
+mailnews_static_dirs = []
 
-component_libs = CONFIG.get('MOZ_APP_COMPONENT_LIBS', '').split()
+mailnews_dirs += ['../mozilla/xpfe/components/autocomplete']
 
-if 'mozldap' in component_libs or CONFIG['MOZ_LDAP_XPCOM']:
-    app_libxul_static_dirs += [bridge_reldir + 'ldap/sdks/c-sdk']
-    app_libxul_dirs += [bridge_reldir + 'ldap/xpcom']
+if CONFIG['MOZ_LDAP_XPCOM']:
+    mailnews_static_dirs += ['../ldap/sdks/c-sdk']
+    mailnews_dirs += ['../ldap/xpcom']
 
-if 'mork' in component_libs or CONFIG['MOZ_MORK']:
-    app_libxul_dirs += [bridge_reldir + 'db']
+if CONFIG['MOZ_MORK']:
+    mailnews_dirs += ['../db']
 
-app_libxul_dirs += [bridge_reldir + 'mailnews']
+mailnews_dirs += ['../mailnews']
 

--- a/mail/app.mozbuild
+++ b/mail/app.mozbuild
@@ -1,40 +1,35 @@
 # 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 = []
 app_libxul_static_dirs = []
 
-# Invoked from /mozilla.
-if not CONFIG['COMM_BUILD']:
-    if CONFIG['MOZ_APP_COMPONENT_LIBS']:
-        bridge_reldir = '../'
-        include('../bridge/bridge.mozbuild')
-        app_libxul_dirs += ['../mail/components']
+include('../bridge/bridge.mozbuild')
+
+if not CONFIG['MOZ_INCOMPLETE_EXTERNAL_LINKAGE']:
+    app_libxul_dirs = mailnews_dirs
+    app_libxul_static_dirs = mailnews_static_dirs
+    app_libxul_dirs += ['../mail/components']
 
-    if not CONFIG['LIBXUL_SDK']:
-        include('/toolkit/toolkit.mozbuild')
+if not CONFIG['LIBXUL_SDK']:
+    include('/toolkit/toolkit.mozbuild')
 
-    if CONFIG['MOZ_EXTENSIONS']:
-        add_tier_dir('app', 'extensions')
+if CONFIG['MOZ_INCOMPLETE_EXTERNAL_LINKAGE']:
+    add_tier_dir('app', mailnews_static_dirs, static=True)
+    add_tier_dir('app', mailnews_dirs)
 
-else:
-    bridge_reldir = ''
-    include('/bridge/bridge.mozbuild')
+if CONFIG['MOZ_EXTENSIONS']:
+    add_tier_dir('app', 'extensions')
 
-    if CONFIG['MOZ_INCOMPLETE_EXTERNAL_LINKAGE']:
-        add_tier_dir('app', app_libxul_static_dirs, static=True)
-        add_tier_dir('app', app_libxul_dirs)
+add_tier_dir('app', CONFIG['MOZ_BRANDING_DIRECTORY'])
 
-    if CONFIG['MOZ_COMPOSER']:
-        add_tier_dir('app', 'editor/ui')
-
-    add_tier_dir('app', CONFIG['MOZ_BRANDING_DIRECTORY'])
+if CONFIG['MOZ_COMPOSER']:
+    add_tier_dir('app', '../editor/ui')
 
-    if CONFIG['MOZ_CALENDAR']:
-        add_tier_dir('app', 'calendar/lightning')
+if CONFIG['MOZ_CALENDAR']:
+    add_tier_dir('app', '../calendar/lightning')
 
-    add_tier_dir('app', 'chat')
-    add_tier_dir('app', 'mail')
-
+add_tier_dir('app', '../chat')
+add_tier_dir('app', '../mail')

--- a/moz.build
+++ b/moz.build
@@ -1,8 +1,4 @@
 # 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['COMPILE_ENVIRONMENT']:
-    include('/' + CONFIG['MOZ_BUILD_APP'] + '/app.mozbuild')
-

--- a/suite/app.mozbuild
+++ b/suite/app.mozbuild
@@ -1,39 +1,33 @@
 # 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 = []
 app_libxul_static_dirs = []
 
-# /mozilla build system.
-if not CONFIG['COMM_BUILD']:
-    if CONFIG['MOZ_APP_COMPONENT_LIBS']:
-        bridge_reldir = '../'
-        include('../bridge/bridge.mozbuild')
+include('../bridge/bridge.mozbuild')
+
+if not CONFIG['MOZ_INCOMPLETE_EXTERNAL_LINKAGE']:
+    app_libxul_dirs = mailnews_dirs
+    app_libxul_static_dirs = mailnews_static_dirs
 
-    if not CONFIG['LIBXUL_SDK']:
-        include('/toolkit/toolkit.mozbuild')
+if not CONFIG['LIBXUL_SDK']:
+    include('/toolkit/toolkit.mozbuild')
 
-    if CONFIG['MOZ_EXTENSIONS']:
-        add_tier_dir('app', 'extensions')
+if CONFIG['MOZ_INCOMPLETE_EXTERNAL_LINKAGE']:
+    add_tier_dir('app', mailnews_static_dirs, static=True)
+    add_tier_dir('app', mailnews_dirs)
 
-# Our build system.
-else:
-    bridge_reldir = ''
-    include('/bridge/bridge.mozbuild')
+if CONFIG['MOZ_EXTENSIONS']:
+    add_tier_dir('app', 'extensions')
 
-    if CONFIG['MOZ_INCOMPLETE_EXTERNAL_LINKAGE']:
-        add_tier_dir('app', app_libxul_static_dirs, static=True)
-        add_tier_dir('app', app_libxul_dirs)
+if CONFIG['MOZ_COMPOSER']:
+    add_tier_dir('app', '../editor/ui')
 
-    if CONFIG['MOZ_COMPOSER']:
-        add_tier_dir('app', 'editor/ui')
-
-    add_tier_dir('app', CONFIG['MOZ_BRANDING_DIRECTORY'])
+add_tier_dir('app', CONFIG['MOZ_BRANDING_DIRECTORY'])
 
-    if CONFIG['MOZ_CALENDAR']:
-        add_tier_dir('app', 'calendar/lightning')
+if CONFIG['MOZ_CALENDAR']:
+    add_tier_dir('app', '../calendar/lightning')
 
-    add_tier_dir('app', 'suite')
-
+add_tier_dir('app', '../suite')