Comment 71 for bug 249340

The strace output starts with:

execve("/usr/bin/localedef-real", ["/usr/bin/localedef-real", "--no-archive", "--magic=20051014", "-i", "en_NZ", "-c", "-f", "UTF-8", "en_NZ.UTF-8"], [/* 42 vars */])

Adjust to suit the locales you actually have installed.

(I moved /usr/bin/localedef to /usr/bin/localedef-real, and created a script in its place that started localedef-real under strace. So now I have lots of strace logs in /var/tmp ... they're about 250kB when it runs to completion and about 150 kB when they stall.)