[luatex] annoying locale error

[Werner LEMBERG]

[I don't know the exact luatex version, sorry]


Folks,


I get the very annoying and extremely unhelpful error message

```
Unable to read environment locale:exit now.
```

This is from a CI container where I can't easily call `locale` to find
out more details.  Additionally, looking up this problem in the
internet, it seems that luatex is sensitive to very subtle details
that can easily be missed (for example, `-` vs. `_`).

Is there a way to make luatex tell me what exactly the problem is?


    Werner