I tried to arrange $subject via
create database icu encoding 'utf8' lc_ctype "en-US-x-icu" lc_collate "en-US-x-icu" template template0;
and got only
ERROR: invalid locale name: "en-US-x-icu"
which is unsurprising after looking into the code, because createdb()checks those parameters with check_locale() which only knows aboutlibc-defined locale names.
Is there some way I'm missing, or is this just a not-done-yet feature?
regards, tom lane