Updated dav1d from 0.5.1 to 1.5.3 as recommended by Andrew with the patch to switch from Meson to Cmake which was a lot of work for him to provide due to a lot more .obj's and a lot of other changes needed. Debian 32-bit, which is i386 instead of x86_64, compiled 1.5.3 with no problems (at NASM 2.13.03) but Ubuntu 16 (also at NASM 2.13.03) erred out with cdef16_xxxx, where I did not write down which xxxx it was (avx2, avx512, or sse).  But will look at it again.

I will have to update the Manual yet..