-override twostep := $(if $(DATADIR),$(shell if $(TEST) -d $(call quote,$(DATADIR)); then $(PRINTF) '%s\n' '1'; fi),)
+override twostep := $(if $(DATADIR),$(call not,$(shell for dir in $(foreach dir,$(DATADIR),$(call quote,$(dir))); do if $(TEST) '!' -d "$$dir"; then $(PRINTF) '%s\n' '0'; fi; done)),)