I have recently send-pr'd this exact issue.  IMHO, <ctype.h> should support
locales of ISO 8859-1 and -2 in some way.  The "correct" fix is that the
user sets a locale implying 8859-1 (for instance) as a character set, and
<ctype.h> functions acquire it.

The way to do this is have the _ctype_ array be a pointer, which initially
points at the ASCII lookup table (in the C locale), but which points at
the table relevant to the current locale for other locales, if this table
is known.  8859-1 and 8859-2 would be the first targets to implement, because
they're well documented standards.

I would love to see this change, and if someone would like to help me with
the details of getting the right tables, I'd be happy to try to implement
it.

It would add at least one test and one assignment to the C stdlib startup
code.

Ideally, the kernel would inherit this change; the behavior of stty lcase
will be wrong otherwise, I belivee.

-s
(that's a typo, not a spelling error.)