Handle /usr/ports/infrastructure/db/user.list locally

Hi porters,

the Porting Guide [1] mentions this:

"20. If the application needs to create a user or a group, choose the
lowest free id from /usr/ports/infrastructure/db/user.list for your port
to use and don't forget to include that file in your commit."

I would like to create a port e.g. at /usr/ports/localhost/localport
which needs to add a user. How to handle the user.list file, if it is
not going to get committed? Whatever user id I would choose, it will
certainly lead to conflicts whenever some other port starts using the
same ids. How to handle this locally without conflicting with others?

Regards,
-- 
Christian

[1] <https://www.openbsd.org/faq/ports/guide.html>