locale issue on sid gnome build

[Baurzhan Muftakhidinov <baurthefirst@gmail.com>]

Good day,

I've built a sid-based image on web build service,
and found that gnome-terminal is refusing to start.

It turns out 'locale' command shows that LANG=C
and gnome-terminal is unable to start because of that.

Is this a known issue?