* Replace OpenBSD regex library with PCRE2.
PCRE2 has way better performance than the OpenBSD
library (something around 20 times faster).
The following flags are enabled for every pattern:
- PCRE2_UTF
- PCRE2_MATCH_INVALID_UTF
- PCRE2_NO_UTF_CHECK
All the others are optional.
Changes made:
- Adds PCRE2 as subproject.
- Changes the API away from POSIX to PCRE2.
- Edits many regex patterns because:
- ' ' is skipped in patterns, if the EXTENDED flag is set for matching. '\s' must be set now.
- '.' doesn't match newlines by default.
- Changes the API so matches and their groups are bundled into PVectors.
- Moves the regex component to rz_util.
* Fix cross build - add copy of PCRE2 dependecy
Meson currently doesn't support subprojects to be native and non-native at the same time.
See: https://github.com/mesonbuild/meson/issues/10947
Unfortunately, sdb depends on rz_util which in turn depends on PCRE2.
Excluding PCRE2 from the native build makes linking of rz_util not possible anymore.
Adding it, will make Meson complain that the dependencies cannot be mixed.
Hence, we compile a copy of PCRE2 for the native build if required.
