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

[Paolo Bonzini]

>> I would rewrite them at the very least as
>>
>> AC_PROG_AWK
>> AC_PROG_CXX
>>
>> if test "${use_libtool}" = "yes"; then
>> AC_LIBTOOL_WIN32_DLL
>> AM_PROG_LIBTOOL
>> fi
> 
> I think that should use AS_IF instead.

Does AS_IF put required macros outside its expansion?  That's a
cool feature if it does.

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.

Paolo