diff --git a/make/projects-dir.mk b/make/projects-dir.mk
index 86cba5a7..508ddf98 100644
--- a/make/projects-dir.mk
+++ b/make/projects-dir.mk
@@ -87,6 +87,9 @@ purge:
 update pull: purge cvs-update git-pull
 	touch pull.done
 
+rebuild-subdirs:
+	FORCE_REBUILD_SUBDIRS=true make all
+
 cvs-update:
 	rm -f $@.done
 	make $@.done