Unfortunate frustrations in this thread aside... out of pure interest:

Omar Polo on Thu, Aug 01 2024:
> Then, we can't use strftime() since it depends on the locale.

Why not strftime_l, then?

> +	now = time(NULL);
> +	lt = localtime(&now);

You take the local time...

> +	offset = lt->tm_gmtoff;
> +	tz = lt->tm_zone;

extract the time zone info...

> +	r = snprintf(buf, sizeof(buf),
> +	    "%s, %d %s %d %02d:%02d:%02d %c%02d%02d (%s)",
> +	    day[lt->tm_wday], lt->tm_mday, month[lt->tm_mon],
> +	    lt->tm_year + 1900,
> +	    lt->tm_hour, lt->tm_min, lt->tm_sec,
> +	    offset >= 0 ? '+' : '-',
> +	    abs((int)offset / 3600),
> +	    abs((int)offset % 3600) / 60,
> +	    tz);

and print it using the english month and weekday names.

Seems to me something like the following should do the trick.

NB: Calling date() twice in puthead() seems wrong and is useless anyway,
since it never returns NULL.

char *
date(void)
{
	static locale_t cloc;
	static char buf[40];
	struct tm *lt;
	time_t now;
	size_t n;

	if (cloc == (locale_t)0) {
		cloc = newlocale(LC_ALL, "C", 0);
		if (cloc == (locale_t)0)
			errx(1, "newlocale");
	}

	now = time(NULL);
	lt = localtime(&now);
	if (lt == NULL)
		errx(1, "localtime");
	n = strftime_l(buf, sizeof buf, "%a, %d %b %Y %T %z (%Z)", lt, cloc);
	if (n == 0)
		errx(1, "strftime_l");

	return buf;
}