not consider building in arm

[Aristoeu]

Minimal, reproducible code sample, a copy-pastable example if possible

Build in arm

Problem description

The code in setup.py does not seem to consider installing numcodecs in arm.

if have_cflags:
    # respect compiler options set by user
    pass
elif os.name == 'posix':
    if disable_sse2:
        base_compile_args.append('-mno-sse2')
    elif have_sse2:
        base_compile_args.append('-msse2')
    if disable_avx2:
        base_compile_args.append('-mno-avx2')
    elif have_avx2:
        base_compile_args.append('-mavx2')

When there is no CFLAGS environmental variable defined, it will always add flags about sse2 and avx2, but all the four flags -mno-sse2, -msse2, -mno-avx2, and -mavx2 are not supported in linux/arm64 architecture. To build it successfully, I have to add some cflags mannually to ignore appending the flags.

Version and installation information

Please provide the following:

• Value of numcodecs.__version__: latest
• Version of Python interpreter: 3.8
• Operating system (Linux/Windows/Mac): Linux
• How NumCodecs was installed (e.g., "using pip into virtual environment", or "using conda"): pip install

[joshmoore]

Hi @Aristoeu. Did you see https://github.com/zarr-developers/numcodecs/pull/315/files#diff-60f61ab7a8d1910d86d9fda2261620314edcae5894d5aaa236b821c7256badd7R32 (but also the associated discussion)?