Thunderbird build bustage from bug 237745, try #2

toolkit/components/Makefile.in

@@ -68,10 +68,15 @@ ifeq ($(OS_ARCH),WINNT)
 DIRS += alerts
 endif
 
-DIRS += startup downloads build
+DIRS += downloads
 
 endif
 endif
 endif
 
+DIRS += \
+	startup \
+	build \
+	$(NULL)
+
 include $(topsrcdir)/config/rules.mk