and remove some unnecessary checks while we're at it.

match() and sub() functions (gcc does so at least).

This mostly moves out functions that are not on the fast path and
we don't try to inline. Also just clears up a lot of clutter.

sub methods.

Currently with even more code repetition that needs to be factored out.

files generated for testing.

Still with plenty of repeated code to be factored out.

The implementation is not trivial, and I'm still not entirely clear
on the use case for Varnish/VCL. We probably will need partial
matching to implement matches against the request body.

so that backref/namedref are guaranteed to return strings in workspace.

There's still a bit of code repetition to be factored out.

for use by the backref/namedref functions.

This brings about a major refactoring, to factor out common code for
regex compiles and matches.

failure messages.

after using pcre2_match_data_create_from_pattern() to create match_data.