Almost a year ago, when Crux jumped from 2.4 to 2.5, locales were handled differently. And for some reason, I always seem to forget them. This is just to remind myself of the commands I used to set them up, with en_US as a vanilla example.
localedef -i en_US -f ISO-8859-1 en_US
localedef -i en_US -f ISO-8859-1 en_US.ISO-8859-1
localedef -i en_US -f UTF-8 en_US.utf8
The available options are in /usr/share/i18n/locales/, which is the part I always seem to forget. And that is, after all, why this blog is here: To remind me of stuff. … 
do what i do: make a symlink with a ridiculously long name in /var!