Rework Makefiles one more time.

- use printf to print commands rather than echo, which it may not have
  support for escape sequences (-e).
- Remove DESTDIR from SBINDIR, MANDIR, LIBDIR and INCLUDEDIR so that
  you can override it.

--HG--
extra : convert_revision : xtraeme%40gmail.com-20100124125958-8mscedj5ntf288jd

Makefile

@@ -18,8 +18,8 @@ install:
 		$(MAKE) -C $$dir install || exit 1;	\
 	done
 	@echo
-	@echo "Binaries have been installed into $(SBINDIR)."
-	@echo "Librares have been installed into $(LIBDIR)."
+	@echo "Binaries have been installed into $(DESTDIR)$(SBINDIR)."
+	@echo "Librares have been installed into $(DESTDIR)$(LIBDIR)."
 	@echo
 	@echo "WARNING: Don't forget to rerun ldconfig(1)."
 	@echo