[RFC] Update to current automake/autoconf/libtool versions.

[Ian Lance Taylor]

Alan Modra <amodra@bigpond.net.au> writes:

> I'm concerned that this proposal may be raising the bar too high.
> How long has it been since some poor fool^H^H^H^H^H^H^H^H^Hbrave soul
> attempted to modernize binutils configury?

It's only been a bit over five years since I reworked binutils
configury to use automake and libtool.

I guess it was about two years before that that Ken Raeburn and I
changed the binutils to use autoconf.

I'm sure I don't know why autoconf 2.5 is not called autoconf 3.
Still, switching to autoconf 2.5 is surely a smaller change than
either of those.

It should be easy enough to extend AC_PREREQ a bit to make sure that
people use the correct version of autoconf for the directory in
question.

Perhaps --enable-maintainer-mode could be extended to specify a PATH
to use to find the tools.

Ian