RFC: Update top level libtool files

[Nick Clifton]

Hi Joseph,

> As per previous discussions on the issue: it's necessary to revert libtool 
> commit 3334f7ed5851ef1e96b052f2984c4acdbf39e20c, see 
> <https://gcc.gnu.org/ml/gcc-patches/2011-01/msg00520.html>.

OK - thanks for that pointer.

> I do not know 
> if there are other local libtool changes that are not in version 2.4.6; it 
> would be necessary to check all differences from 2.2.7a to determine 
> whether any need to be re-applied to 2.4.6.

*sigh*  It seems that 2.2.7a was not an official release.  At least I could
not find a tarball for that specific version on the ftp.gnu.org/libtool archive.
(There is a 2.2.6b release and a 2.2.8 release but no 2.2.7<anything>).  So it
looks like we have been using a modified set of sources for a long time now.

Maybe I would be better off not rocking the boat, and just submit the Fedora
sys_path patch for consideration instead...

 
> For that matter, these trees are also using very old autoconf and automake 
> versions and using the current versions of those (2.69 and 1.15.1) would 
> be a good idea as well.  Hopefully version dependencies are loose enough 
> that it's possible to update one tool at a time (so update libtool without 
> needing to update autoconf or automake at the same time).

Oh gosh - I would love to see that done.  But the last time I tried I ended 
up going down a rabbit hole of autoconf/automake problems that just never 
ended.  So I gave up. :-(  Maybe someone with more autoconf-fu than me will
have a go one day though.

Cheers
  Nick