Makefile improvements

Makefile

@@ -1,4 +1,22 @@
 .PHONY: doc
+.PHONY: tests
+
+default:
+	@/bin/echo -e "Usage:\n\tmake diet - compile with diet libc\n\tmake lib  - compile with normal gnu libc\n\tmake tests\n\tmake doc"
+
+lib:
+	make -C src lib
+
+diet:
+	make -C src diet
+
+tests:
+	make -C tests
 
 doc:
 	doxygen
+
+clean:
+	make -C src clean
+	make -C tests clean
+	rm -rf doc

src/Makefile

@@ -20,3 +20,6 @@ match: match.c
 	${CC} -o $@ -DDEBUG=2 -DCMDTOOL -DTEST $<
 
 it: match
+
+clean:
+	rm -f $O