> Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
>
>
>>> ERROR: regexp.test: regexp-quote: regexp/extended: (char 254 #\þ
>>> "þ") -
>>> arguments: ((regular-expression-syntax "make-regexp" "empty
>>> (sub)expression" #f ("þ")))
>>
>> Hm?
>>
>>> FAIL: regexp.test: regexp-quote: regexp/extended: (string "aX" 254
>>> #\þ "aþ" "aþ")
>>> FAIL: regexp.test: regexp-quote: regexp/extended: string of all chars
>>
>> Can you try:
>>
>>  (setlocale LC_ALL "en_US.ISO-8859-1") ;; or some other ISO-8859-1 locale
>>  (let* ((s (string (integer->char 254)))
>>         (q (regexp-quote s)))
>>    (regexp-exec (make-regexp q regexp/extended) s))

[...]

> scheme@(guile-user)> (setlocale LC_ALL "en_US.ISO8859-1")
> $1 = "en_US.ISO8859-1"
> scheme@(guile-user)> (let* ((s (string (integer->char 254))) (q
> (regexp-quote s))) (regexp-exec (make-regexp q regexp/extended) s))
> ERROR: In procedure make-regexp:
> ERROR: In procedure make-regexp: empty (sub)expression

This looks like a bug of Darwin’s regcomp that’s likely to be solved by
using Gnulib’s ‘regex’ module.  If you don’t mind, I’ll provide you
with a new tarball to test when we’re done with the other issues.

Thanks for your patient investigation!

Ludo’.