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

[Andrew Cagney]

> 
> Yes, I suppose that would be required to support a single
> --enable-maintainer-mode at the top level.
> 
> On the other hand, I personally usually run a basic configure at the
> top level, and then run configure again in the subdirectories for
> which I want to use --enable-maintainer-mode.

So _thats_ how to avoids maintainer mode on all but one directory...

Andrew