diff --git a/make/topdir.mk b/make/topdir.mk
index a0ac9b76..3633a2cd 100644
--- a/make/topdir.mk
+++ b/make/topdir.mk
@@ -4,6 +4,8 @@ clean: topdir.clean
 distclean: topdir.distclean
 config:
 
+SUBDIRS ?= $(wildcard inst/pre make tools include lib bin util cfg doc test inst/post)
+
 ifneq ($(wildcard $(TOPDIR)/make/defs.mk),)
   include $(TOPDIR)/make/defs.mk
 endif