[ Patch comments in three pieces.]

Attached is a pacth against 7.2 which adds locale awareness to the
character classes of the regular expression engine.

...

> > I still think the xdigit class could be handled the same way the digit
> > class is (by enumeration rather than using the isxdigit function). That
> > saves you a cicle, and I don't think there's any loss.
>
> In fact, I will email you when I apply the original patch.

I miss that case :-(. Here is the pached patch.

...

Here is a patch which addresses Tatsuo's concerns (it does return an
static struct instead of constructing it).