1. export GLIBC_TUNABLES=glibc.cpu.hwcaps=-AVX512
2. Add _dl_printf("p -- %s\n", p); just before switch(nl) in
sysdeps/x86/cpu-tunables.c
3. compiled and run ./testrun.sh /usr/bin/ls
you will get:
p -- -AVX512
p -- LC_ADDRESS=en_US.UTF-8
p -- LC_NUMERIC=C
...
The function, TUNABLE_CALLBACK (set_hwcaps)
(tunable_val_t *valp), checks far more than it should and it
should stop at end of "-AVX512".