community/phoc: build embedded wlroots

Phoc requires a few out of tree patches to wlroots, and trying to maintain separate package forks of wlroots in aports to apply these patches is a maintenance burden and doesn't always work as expected (e.g. sometimes apk ignores it and installs an unpatched wlroots, breaking phoc for users)

This basically gives up the fight for now and embeds purism's wlroots fork w/ their patches to support phoc/phosh.