I tried a downgrade to nasm 5.14 but it still produces errors. nasm
5.13 is too old and Arch no longer has it in the archive. However, the
month-end build was working fine; it must be an Arch update from the
last week.
I tried disable-dav1d; disable dav1d + libaom + opus; and finally
clang + disable-dav1d. In all 3 cases I get errors.

 I attach the logs.