Since I like to keep up to date (and it didn’t work), I’ve submitted my first patch to an existing Gentoo build, specifically, mod_php. It utilized an old patch that was valid for elder revisions of PHP. Oddly, the bugs were fixed in PHP 4.3.5 for Apache 2, but not Apache 1; so I removed the patches for Apache 2, and created a new ebuild. It’s built, and works fine.

[Update: Interesting. Robin Johnson included a patch which is exactly the same, roughly 10 hours later than mine, but only after browbeating me for my submission, and without credit. Shame on you, sir.]