Avoid ‘new File::Temp’ in Perl scripts.

Avoid ‘new File::Temp’ in Perl scripts.

Despite what the documentation says, ‘new File::Temp’ does not work
reliably in perl 5.6.x.  Rather than figure out exactly what is wrong
with it, let’s just stick to ‘tempfile’.

 * bin/autom4te.in (handle_output): Use tempfile function instead of
   object-oriented File::Temp interface.
 * bin/autoreconf.in (install_aux_file): Likewise.