diff --git a/make/rules.in b/make/rules.in
index d5703e7a57..48570df4fa 100644
--- a/make/rules.in
+++ b/make/rules.in
@@ -57,6 +57,7 @@ all: subdirs ${TARGETS} testdirs
 ###
 ### Makefile may define:
 ###	SUBDIRS
+###	DEPDIRS
 
 ALL_SUBDIRS = ${SUBDIRS} nulldir
 ALL_TESTDIRS = ${TESTDIRS} nulldir
@@ -244,7 +245,7 @@ distclean maintainer-clean::
 	rm -f Makefile
 
 depend:
-	@for i in ${ALL_SUBDIRS}; do \
+	@for i in ${ALL_SUBDIRS} ${ALL_TESTDIRS}; do \
 		if [ "$$i" != "nulldir" -a -d $$i ]; then \
 			echo "making depend in `pwd`/$$i"; \
 			(cd $$i; ${MAKE} ${MAKEDEFS} DESTDIR="${DESTDIR}" $@) || exit 1; \