Hi Dave.

I have just noticed that for config.guess and config.sub to be updated, no
autoreconf or dh_autotools-dev is needed, because of how Makefile was made.

In Makefile, @row 80:

  LIBTOOLIZE_INSTALL = `libtoolize -n -i >/dev/null 2>/dev/null && echo -i`

  configure:
          libtoolize -c $(LIBTOOLIZE_INSTALL) -f
          cp include/install-sh .
          aclocal -I m4
          autoconf

This runs libtoolize -c -i which updates those files.

The file debian/rules runs `make default`, which at some point calls the target
above (`make configure`). But the file configure already exists, so it does not
run.

Curiously, running `dpkg-buildpackage` twice, causes configure file to be
deleted, and the build completes without errors.

So, answering to your question:

 > Nowdays, the generated files in the 3.2.4 tarball created via a
 > 'make dist' rule. I run that on an up to date debian unstable box
 > with autoconfig 2.69 installed to generate the files, so the
 > question I have is this: why is an up-to-date build box generating
 > "out of date" configure/m4 scripts? What, exactly, is out of date,
 > and how do I ensure that the pre-build config files are correctly
 > up-to-date?

The configure file comes shipped with the debian package, so that specific file
is not re-generated and is always out of date.
By the looks of the Makefile, there is no need to include autoreconf or 
autotools-dev in debian/rules, but to force `make distclean` to `rm configure`.

Attached is a patch that summarizes that, but for some reason it does not work
when running with parallel jobs enabled. But you can get the idea :)

Regards.
-- 

Fernando Seiti Furusato
IBM Linux Technology Center