> > -                (!ctx->match_all || ctx->ptr == state->end)) {
> > +                ctx->ptr == state->end) {
> 
> Why this check is not needed anymore?
> 
After stepping through the code for that regex that fails, I concluded 
that the condition shouldn't depend on ctx->match_all at that point 
after all.

> > -                    status = SRE(match)(state, pattern + 2*prefix_skip);
> > +                    status = SRE(match)(state, pattern + 2*prefix_skip, 
> state->match_all);
> 
> > -            status = SRE(match)(state, pattern + 2);
> > +            status = SRE(match)(state, pattern + 2, state->match_all);
> 
> state->match_all is used but it is never initialized.

I thought I'd initialised it in all the places it's used.

I admit that I find the code a little hard to follow at times... :-(