The BSD patches for 14.0 are ready for GIT checkin (next time I boot the desktop). I tested on Debian 9.1 32-bit and Ubuntu 16 and of course, Fedora 32 -- just because even though they are mostly specific to only BSD, it is just a lot easier to find a problem now then having to backtrack later.
yeah, thanks!
P.S. this problem "Fix for freebsd 14 build OpenEXR /// cflags pkg-config does not work for some reason/" is, I believe, the reason why I could never get OpenEXR upgraded from 2.4.1 to 3.1.4 as provided by Manuel V. I could not get "without openexr" working for Ubuntu 16 which has a too low version default of cmake.
well, *I think* freebsd 14 problem is different - it uses their own version of pkg-config, so it probably interacted with shell strangely when called from configure script. But I haven't investigated your openexr upgrade problem in detail, sorry!
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