www/mod_php85 MidnightBSD

`textproc/libxml2` 2.15 changed SONAME from `libxml2.so.2` to `libxml2.so.16` **and** removed ELF symbol versioning entirely — the new library defines no `LIBXML2_*` versions at all. Consumers built against the old library were never rebuilt, so they still record a dependency on `libxml2.so.2` plus version requirements nothing can satisfy, and fail at load time: ``` ld-elf.so.1: /usr/local/lib/libxml2.so.2: version LIBXML2_2.4.30 required by /usr/local/lib/libevdocument3.so.4 not defined ``` ### Scope `Tools/scripts/bump_revision.pl -f -l textproc/libxml2` — **436 Makefiles**: 323 revisions incremented, 113 gained a `PORTREVISION` line. The diff touches nothing but `PORTREVISION` lines (verified: `git diff -U0` shows no other changed line), and spot-checked ports still …

## Summary - register PHP 8.5 in the PHP framework and default-version documentation - add PHP 8.4 and 8.5 extension ABI metadata - add and register www/mod_php85 from the local FreeBSD ports tree - remove the FreeBSD 15-only OSVERSION argon2 condition - provide the MidnightBSD pthread configure result needed for Apache ZTS builds ## Validation - all 56 PHP 8.5 origins parse with PHP_DEFAULT=8.5 - bmake makesum, patch, build, fake, and package pass for lang/php85 - bmake makesum, patch, build, fake, and package pass for www/mod_php85 - bmake check-license passes for both ports - generated php85-8.5.9.mport and mod_php85-8.5.9.mport packages - PHP extension ABI resolves to 20250925-zts for PHP 8.5 and 20240924-zts for PHP 8.4 on this host …