Howto tell pg_ctl to use a non-default directory for config files

Hi,

FYI: I am pretty new to PostgreSQL, and I am intending to migrate from an MariaDB/Galera cluster to PostgreSQL with either Patroni or pg_auto_failover. And, I have successfully tested a stand-alone database with my client of interest [1], both running inside a FreeBSD jail.

Question:
Is there a way to tell PostgreSQL to look for config files in e.g. /usr/local/etc/postgres, where normally all config files reside in FreeBSD? [2]

Thanks and regards,
Michael

[1] https://dbmail.org
[2] As an intermediate solution I am using soft links from $PGDATA to /usr/local/etc/postgres