AVX (and friends) on macOS Rosetta

Rosetta translates all x86_64 instructions, but it doesn’t support the execution of some newer instruction sets and processor features, such as AVX, AVX2, and AVX512 vector instructions. If you include these newer instructions in your code, execute them only after verifying that they are available. For example, to determine if AVX512 vector instructions are available, use the sysctlbyname function to check the hw.optional.avx512f attribute.

https://developer.apple.com/documentation/apple_silicon/about_the_rosetta_translation_environment?language=objc

The qDetectCpuFeatures() logic in qsimd.cpp may need to adjust to this, if the existing xgetbv-based logic does not pick it up.