Possibility to add CORS domains permanently

I'm unable to test right now, but I think if you set the variable using something like this:

<VirtualHost hostname:80>
   ...
   SetEnv CORS_HOSTS desired.domain.name
   ...
</VirtualHost>

The PHP code should read the value (line 56) and insert it into $AUTHORIZED_HOSTNAMES variable (line 58):

NOTE:
You need to restart apache2 after edit your config.