Feature request: Enable DCG (\+)/2 by default

[Jean-Luc-Picard-2021]

I can recompile Scryer Prolog by uncommenting this line in src/lib/dcgs.pl:

%% dcg_constr(\+ _). % 7.14.11 - not (existence implementation dep.)

And then DCG not works, although not extremly efficient compared to other Prolog systems. Would it be possible to have this uncommented by default?

In Trealla Prolog library/dcgs.pl it is now uncommented:

dcg_constr(\+ _). % 7.14.11 - not (existence implementation dep.)

That its now uncommented in Trealla Prolog is very handy, no extra juggling with git and having locally a changed file, to have the DCG not feature on.