--- a/dom/Makefile.in
+++ b/dom/Makefile.in
@@ -7,17 +7,17 @@ DEPTH		= @DEPTH@
 topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
 MODULE		= dom
 
-DIRS = \
+PARALLEL_DIRS = \
   interfaces/base \
   interfaces/canvas \
   interfaces/core \
   interfaces/html \
   interfaces/events \
   interfaces/devicestorage \
   interfaces/contacts \
   interfaces/settings \
@@ -32,23 +32,20 @@ DIRS = \
   interfaces/xul \
   interfaces/storage \
   interfaces/json \
   interfaces/offline \
   interfaces/geolocation \
   interfaces/notification \
   interfaces/svg \
   interfaces/smil \
-  $(NULL)
-
-DIRS += \
   interfaces/apps \
   $(NULL)
 
-DIRS += \
+PARALLEL_DIRS += \
   apps \
   base \
   activities \
   bindings \
   battery \
   browser-element \
   contacts \
   alarm \
@@ -70,24 +67,24 @@ DIRS += \
   system \
   ipc \
   identity \
   workers \
   camera \
   $(NULL)
 
 ifdef MOZ_B2G_RIL
-DIRS += \
+PARALLEL_DIRS += \
   telephony \
   wifi \
   $(NULL)
 endif
 
 ifdef MOZ_B2G_BT
-DIRS += \
+PARALLEL_DIRS += \
   bluetooth \
   $(NULL)
 endif
 
 # bindings/test is here, because it needs to build after bindings/, and
 # we build subdirectories before ourselves.
 TEST_DIRS += \
   tests \