A newbie asks...

[Robert Lowe]

Sorry to interrupt your normally scheduled programming...

I've read most of the documentation or tutorials I could find, but I'm
afraid much of it went right past me.  Most of the tutorials seem to focus
on very straightforward examples, e.g. 'hello world' stuff.  I have a small
project, and I decided I should attempt to take the plunge into the world
of autoconf/automake.  I managed to create a useable configure.ac, and a
few Makefile.am's in a couple of subdirectories, and the config.h.in is
constructed.  Now comes the question of how to make this wonderful build system
help me do something beyond what I might have managed myself with simple 
Makefiles.
My application uses:

1. POSIX threads
   Is this solved as easily as adding the acx_pthread macro in aclocal.m4, then
   calling it in configure.ac and using the defined variables to properly set
   my foo_CFLAGS, foo_LIBS (or do I use LDADD?), etc., in my Makefile.am?

2. A header file which seems to be in different places on some platforms
   (net/ethernet.h, sys/ethernet.h, and perhaps others).  What am I supposed to
   construct to define something that will help me include the correct header
   file?

Perhaps I just glossed over an obvious example, so if I did, just point me to 
the
correct location in the docs, and I'll attempt to take the next steps by myself.
Thanks for your patience!!!

-Robert