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

[Steve Ellcey]

> It might be, but I was just trying to be helpful and make the libtool 
> patch as small (and easy to maintain as possible).  Other cleanups, 
> while much appreciated, are tangential.
> 
> (Besides, I am going on vacation on the 22nd and wanted to get the patch 
> in before that!)
> 
> Paolo

OK, I will do the original patch (with your changes) first and leave
the rest for later.

Steve