provided code

Makefile

@@ -0,0 +1,13 @@
+CLEAN_SUBDIRS = src doc tests
+
+all::
+	@echo "This makefile has only 'clean' and 'check' targets."
+
+clean::
+	for d in $(CLEAN_SUBDIRS); do $(MAKE) -C $$d $@; done
+
+distclean:: clean
+	find . -name '*~' -exec rm '{}' \;
+
+check::
+	make -C tests $@