COMPAT_HWCAP_ISA_V
isa2hwcap['v' - 'a'] = COMPAT_HWCAP_ISA_V;
hwcap &= ~COMPAT_HWCAP_ISA_V;
#define has_vector() (getauxval(AT_HWCAP) & COMPAT_HWCAP_ISA_V)