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

[Paolo Bonzini]

>> Does AS_IF put required macros outside its expansion?  That's a
>> cool feature if it does.
> 
> Only with Autoconf 2.60 and newer.

I see; so it's ruled out for now.

>> However, if this is the case, it is also a problem.
>> AM_PROG_LIBTOOL used to expand its subparts via
>> AC_REQUIRE, which would sort of undo the effect of
>> the if statement.
> 
> Yes, I don't think it'll help here.  But also I don't see why CXX should
> come into play here at all, if not by an old 1.5.x libtool.m4 file that
> is picked up by aclocal (without having tested anything, though).

Dave, can you check the content of newlib/aclocal.m4?

Paolo