Paul's Rules of Makefiles  A somewhat tongue-in-cheek title, but
this page lists a few very important rules you should always
keep in mind when creating makefiles. Following these rules will
allow your makefiles to be both pithy and beautiful. And they
will make maintaining and modifying them, and thus your entire
life, a much more pleasant experience.    1. Use GNU make.
Don't hassle with writing portable makefiles, use a portable
make instead!    2. Every non-.PHONY rule must update a file
with the exact name of its target.      Make sure every command
script touches the file "$@"-- not "../$@", or "$(notdir $@)",
but exactly $@. That way you and GNU make always agree.    3.
Life is simplest if the targets are built in the current working
directory.      Use VPATH to locate the sources from the objects
directory, not to locate the objects from the sources directory.
4. Follow the Principle of Least Repetition.      Try to never
write a filename more than once. Do this through a combination
of make v