Final(?) patch to update libtool in GCC and src trees

[Paolo Bonzini]

> My plan is to make the changes you want, test with the new libtool to
> make sure that works, then revert to the old libtool, retest, and check
> in the changes when that works.  It may take a few days.

That's a safe plan.  I suggest a quicker smoke test though: this patch 
should result in no change to configure -- both with old libtool 
compared to CVS, and with new libtool compared to your previous patch.

Paolo