Eli Zaretskii wrote:
>> From: Noam Postavsky <npostavs@gmail.com>
>> Date: Wed, 01 Aug 2018 20:58:22 -0400
>>
>> I think it might make sense to hold onto it, but I don't feel very
>> strongly about it.
> 
> If it's useful, I think it should stay.

OK, revised patchset attached. This keeps the debugging code in question. I took 
the liberty of renaming DEBUG (which clashes with other DEBUGs) to 
EMACS_REGEX_DEBUG.