On Arm, the configure process outputs warnings for not finding AVX support, but that's to be expected on Arm.
-- WARNING: Compiler or processor do not support AVX. Skipping tests -- WARNING: Compiler or processor do not support AVX2. Skipping tests -- WARNING: Compiler or processor do not support AVX-512. Skipping tests
Only probe for AVX on x86 platforms, which avoids the warnings elsewhere.