In dadb8ff2, we disabled support for AVX-512 for all 32-bit UNIX builds completely. Yet those builds are only missing support for AVX-512 state in signal frames. Various tests already exist for existing context switching in 32-bit. In order to keep these tests working, we are re-enabling partial AVX-512 support for UNIX 32-bit. A warning is issued if AVX-512 code is encountered.
Issue: #1312