on the "todolist" target, it also display that line of the Makefile (since, obviously, all the keywords are listed, and ALLFILES includes AUXFILES which includes the Makefile itself

People should be able to figure it out, but at the same time, it should also be fixed.
Other then that, loved the tutorial. I had used the Autotools side of make a lot, but never dove into actually writing a manual Makefile, so this helped a lot (aside from OSDev, this is just a great Makefile tutorial. lol)