Andrew, looking at these today (amongst other things). Will they affect building older version 13.0 of BSD or is that not important? Also, I think we need to add a better and updated section in the manual but not sure about the facts so I have to "think" about it some more.
Will try with 12.1 later ... for now Ports system on 14.0 thankfully build cingg git snapshot even without those patches. They only needed for manual building, it seems.
As far as I understand userland on BSD usually installed/updated separately from small 'core' (compilers, kernel, few utilities). So you can have new python etc on top of supported 12.x OS release ...
Next month I may try to get port2pkgsrc conversion for netbsd, because I found nice workaround for too small / partition - just nfs mount /usr/ports read/write from bigger host machine, in my case using nfsv4 Hopefully it will work for NetBSD too!
Funny that 2 virtual cpu cores at nearly 4ghz can build dynamic version of cingg without thirdparty in just 580 seconds or so ....
so, I tested them on
Slackware 15.0 i586 (static link w/ ffmpeg 6.1 and dynamic with ffmpeg 4.4)
Termux aarch64 (dynamic so far)
Freebsd 14.0 amd64 updated to latest packages
NetBSD 9.2 i386 updated to latest user packages
Ubuntu 16.04 amd64 - static ffmpeg 6.1 without dav1d
currently testing: Debian 11.0 amd64