our $AUTOLOAD;
sub AUTOLOAD {
    # this is used to 'autoload' constants from the constant()
    # XS function.  If a constant is not found then control is passed
    # to the AUTOLOAD in AutoLoader.

    my $constname;
    ($constname = $AUTOLOAD) =~ s/.*:://;
    croak "& not defined" if $constname eq 'constant';
    my $val = constant($constname, @_ ? $_[0] : 0);
    
    if ($! != 0) {
        if ($! =~ /Invalid/ || $!{EINVAL}) {
            $AutoLoader::AUTOLOAD = $AUTOLOAD;
            goto &AutoLoader::AUTOLOAD;
        } else {
            croak "Your vendor has not defined $constname";
    }   }
    eval "sub $AUTOLOAD { $val }";
    goto &$AUTOLOAD;
}