I've been resisting the temptation to enter this debate for long
enough.

If you're going to rework the general method by which libc gets
information from config files in /etc, then a clean fast strategy
presents itself:

The config files, or a parsed or hashed version of them, should reside
in shared memory, and spin locks should be used to enforce consistency
during updates.

Shared memory is not a "required" part of netbsd now as far as i know.
This is a small obstacle compared to the trouble of actually
implementing this.

Notice that, since libc is already shared and dynamically linked,
putting the libc config info in shared memory is architecturally
consistent.

-douzzer