Some ports require a certain user to be on the installed system. Choose a free UID from 50 to 999 and register it either in ports/UIDs (for users) or in ports/GIDs (for groups). Make sure you do not use a UID already used by the system or other ports.

Please include a patch against these two files when you require a new user or group to be created for your port.

Then you can use USERS and GROUPS variables in your Makefile, and the user will be automatically created when installing the port.

The current list of reserved UIDs and GIDs can be found in ports/UIDs and ports/GIDs.