Patch to update libtool in GCC and Src trees

[Paolo Bonzini]

> (3) Should the configure.in's be changed to use the 'modern' libtool 
> initialization macro LT_INIT([shared static win32-dll]) -- which will 
> need to be committed simultaneously or as an integral part of Steve's 
> update; or should they instead continue to use the old 
> 'AC_LIBTOOL_WIN32_DLL; AM_PROG_LIBTOOL' macros?

I prefer to do this one step at a time, because it applies to other 
libraries too.

> (4) Once these questions are answered: Steve, do you want to 'absorb' 
> this patch into your update, so it can be committed atomically?

This would be best.  Steve, please post your patch again in reply to 
this message (I've added back binutils, gdb, and gcc mailing lists) and 
I'll ok it.

I'll look into the "standalone libtool" idea more, but this would 
already be quite a step forward.

Paolo