Add rule to make real (not just phony) targets in submodules

makefile-language

@@ -18,6 +18,9 @@ define SUBMODULEMAKE =
 .PHONY: $1__%
 $1__%:
 	$(MAKE) -C $1 $$*
+
+$1/%:
+	$(MAKE) -C $1 $$*
 endef
 
 $(foreach SUBMODULE,$(SUBMODULES),$(eval $(call SUBMODULEMAKE,$(SUBMODULE))))