Could you add support for ARM SIMD?

[Luciferre]

Currently it only supports Intel X86 machine AVX. We have many use cases on ARM machine. Thanks.

[gouyt13]

Thanks for your interests.
Since we have no coding experience on ARM machines, currently, it is difficult for us to support ARM recently. But we are very happy if you or other open-source contributors can help us implement SIMD on ARM.

[TamimEhsan]

@gouyt13 I propose we use Google highway as fallback to avx2 and avx512. It will be much faster to incorporate and will then support many popular architecture. Then if we want to make special case for any architecture then we can do later iteratively.