I don't know what subs/resubs scripts that you're referring to. You need to use the proper $msgtags in your scripts for sub gifting. I don't think Twitch has any docs on it anywhere (not unusual). I was able to modify my own scripts to work with sub gifting.

An example to get started:
Code:
IF ($msgtags(msg-id).key == subgift) {
  ...do stuff...
}