[php-src] Issue #7863: Replace Libxml2 by Gumbo or Lexbor for HTML parsing

Issue: https://github.com/php/php-src/issues/7863 Comment Author: cmb69 I get your point, but replacing libxml2 with something else is a big change, and I'm not sure if we can do that even for major PHP version (due to subtle and maybe not so subtle BC breaks). It might be more reasonable to provide an alternative PHP extension first (which could live in PECL until it is sufficiently proven). gumbo-php was possibly a good start, but unfortunately gumbo-parser is apparently unmaintained (last commit was made more than 6 years ago). lexbor seems active, but apparently there is no PHP extension using it available. A completely different alternative would be to help libxml2 to better support HTML5 and further character encodings. I'm not sure about the status of that project, but submitting a PR or three there might show.