Replace the winsocket pair sub with this:

sub winsocketpair {
    my $proto = getprotobyname('tcp');
    my $first = 1;

    for (1..5) {

        if ($first) {
            undef $first;
        }
        else {
            carp "winsocketpair failed: $!, retrying"
        }

        socket(my $listener, AF_INET, SOCK_STREAM, $proto)
            or return ();

        socket(my $server, AF_INET, SOCK_STREAM, $proto)
            or return ();

        socket(my $client, AF_INET, SOCK_STREAM, $proto)
            or return ();

        my $true = 1;
        ioctl($client, 0x8004667e, \$true );

        my $addr = sockaddr_in(0, INADDR_LOOPBACK);
        bind($listener, $addr) or return ();
        listen($listener, 1) or return ();
        $addr = getsockname($listener);

        connect($client, $addr) 
            or $! ==  10035 or $! == EINPROGRESS 
            or next;
        my $peer = accept($server, $listener) or next;

        my $false = 0;
        ioctl($client, 0x8004667e, \$false );

        if ($peer eq getsockname($client)) {
            return ($server, $client);
        }

    }
    return ();
}
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And ignore make test--the tests seem to be broken. They sometime pass and sometimes fail?