I reported the issue to the glibc maintainers, but they seem skeptical. <https://sourceware.org/bugzilla/show_bug.cgi?id=20664>
- bug#24601: UTF-8 locale makes lexicographic sort weird mathew
- bug#24601: UTF-8 locale makes lexicographic sort weird Eric Blake
- bug#24601: Update mathew
- bug#24601: Update Paul Eggert
- bug#24601: Update Assaf Gordon
- bug#24601: Update mathew
- bug#24601: Update Assaf Gordon
