gosu prevents running container as unprivileged user

[mtdcr]

When running a container with a fixed unprivileged UID, gosu can not be executed. It would be really nice if gosu could be made optional, for example when a specific environment variable is present.

Currently, I set user: 12345678:12345678, userns_mode: host in docker-compose.yml and provide volumes for /var/www/html and /etc/dovecot/private where this UID may read/write in order to run an unprivileged container, but I need to remove gosu from the entrypoint to make it work.