Default listening configuration is confusing

Description

I tried to revert default listening on IPv6 on RHEL 7, but changed just default config string. But it does not change anything. It seems that value is not ever used.

Request

Comment out default options listen-on {any;}; in default config. Or actually use them and remove custom handling in bin/named/server.c. I think main purpose was different defaults for lwresd. That affects only 9.11. In that version, default values should be commented out in config.c.

That change would make ns_listenlist_default unused and could be removed also.

Links / references

https://gitlab.isc.org/isc-projects/bind9/-/blob/main/bin/named/config.c#L74 https://gitlab.isc.org/isc-projects/bind9/-/blob/main/bin/named/server.c#L8917

edit by @bconry: adjusted links/references as they were broken; revised line numbers are approximated from context as the commit when they were created is unknown