I was limping along for years learning autoconf/make in bits until this
tutorial came out
Autotools: a practitioner's guide to Autoconf, Automake and Libtool
http://www.freesoftwaremagazine.com/books/autotools_a_guide_to_autoconf_automake_libtool
I realized a lot of useful things after that. The main thing that makes
it easy is that a real project is stepped through with lots of side
discussions,
and high-level overviews put things in to perspective. I'd really like
to have
a hard-copy book of that tutorial.
After that, i could understand the autoconf manual. I was on dos/windows
up to nearly yr2000 or so, so i had to learn unix programming, shell
programming, make-file programming, m4, how unix processes work etc,
to be able to look in generated Makefiles and "configure" and see from
that what errors i was making in configure.ac and automake.am.
Learning too many things simultaneously, but i know now.