diff --git a/make/dirs.mk b/make/dirs.mk
index 187aaea6..d15de87e 100644
--- a/make/dirs.mk
+++ b/make/dirs.mk
@@ -47,7 +47,7 @@ endif
 # explicit duplication of pattern-rule is needed, otherwise .PHONY: dirs-all.done won't match
 dirs-all.done: $(PREREQ_DIRS_DONE)
 	touch started-dirs-all.done
-	set -e; for d in $(SUBDIRS_TO_ITERATE) ; do make -wC $$d $*; done
+	set -e; for d in $(SUBDIRS_TO_ITERATE) ; do FORCE_REBUILD_SUBDIRS=true make -wC $$d $*; done
 ifneq ($(DONT_CHECK_PREREQ_DONE),true)
 	touch $@
 endif