> Thanks for the detailed report.
>

You're welcome.

I feel a bit culprit since I lived with that bug for such a long time and
only started debugging today... Shame on me.

(...) About using LANG specifically, any chance that it might interfere
> with
> the system's configured encoding, e.g. UTF-8 vs other? In your example,
> does searching for accented characters work as well?
>

Yes. I added LANG=C then checked succesfully that search succeed with
french guillemet «, accented letters é, ç, and non-breaking space.


> IIUC we can try LC_MESSAGES as the more specialized var. Does
> LC_MESSAGES=en work as well?
>

No. Matches in binary files make the search fail in that case.
-- 
Matthias