improving locale support

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Illumos, FreeBSD, and DragonFlyBSD recently cooperated to make their
locale support better.

Here's the FreeBSD commit:

https://lists.freebsd.org/pipermail/svn-src-head/2015-November/078554.html

Here's a blog post by the FreeBSD committer, bapt, about the changes:

http://blog.etoilebsd.net/post/This_is_how_I_like_opensource

I'd be happy if someone could take a look at and integrate it into
NetBSD too, if useful :)

Thanks,
 Thomas