Patch to update libtool in GCC and Src trees

[Paolo Bonzini]

> Either way, Steve's existing patch needs to be extended to do 
> _something_ with newlib, and that means a few more days of shakedown so 
> the linux-native-newlib guys can test it.

Agreed.

> Ralf W. and I have been working on some refinements for cygwin/mingw 
> libtool in libtool's ToT over the last few weeks.  They are not yet 
> ready, and I certainly do not want to hold back gcc progress waiting on 
> libtool: the 20070318 libtool ToT included in Steve's update works fine 
> as demonstrated above.  However, now that Steve's done all or most of 
> the _hard_ work, what will be the policy going forward with regards to 
> updating external, but embedded, tools like libtool?
> 
> How often will gcc re-import the latest libtool ToT?  Any chance of 
> another -- less disruptive! -- update before 4.THREE.0 ships?

If it were only for me, we could commit to syncing libtool ToT 
periodically at least until libtool 2.0 is out.  But I suspect that to 
convince everybody, libtool would need a more precise notion of 
stable-ness.  After that, it will be the usual mess, the same as for 
Autoconf and Automake... :-)

Paolo