I'm not sure if it this is a good fix or what, but for now, I set $xcart_http_host to my domain minus the www. in config.php.
Then in welcome.tpl, I switched this:
Code:
setcookie("GreetingCookie", $first_last, time()+3600*24*180, "/", $_tmp["host"]);
to
this:
Code:
setcookie("GreetingCookie", $first_last, time()+3600*24*180, "/", $xcart_http_host);
That way, whether people go to doman.com
www.domain.com or subdomain.domain.com, xcart can still grab the cookie.
I'm not sure if I lose anything by doing this. Obviously x-cart moved to the host method for a reason.