It was in fact intentionally broken to find out where removing single-byte locales hurts our users most.

We have a hackathon coming up with devs committed to making UTF-8 work in more base utilities. If that works out, and the most sore points of latin1/koi-8/etc users have been adequately addressed, 5.9 will ship with only the UTF-8 locale (and of course the default "C" locale -- ASCII).

If this approach turns out to be wrong because we cannot get regressions fixed, 5.9 will ship like 5.7 and 5.8 (with UTF-8 and single byte locales).