Disable march=native option when building on Apple M1

[yoshoku]

I failed to install hnswlib with pip on Apple M1. The output error message is as follows:

$ pip install hnswlib
Collecting hnswlib
  Using cached hnswlib-0.6.0.tar.gz (30 kB)

...

Building wheels for collected packages: hnswlib
  Building wheel for hnswlib (pyproject.toml) ... error
  ERROR: Command errored out with exit status 1:

...

  clang: error: the clang compiler does not support '-march=native'
  error: command '/usr/bin/clang' failed with exit code 1
  ----------------------------------------
  ERROR: Failed building wheel for hnswlib
Failed to build hnswlib
ERROR: Could not build wheels for hnswlib, which is required to install pyproject.toml-based projects
$

The cause of this error is that Apple M1's clang does not support the march=native option. I have fixed setup.py so that the march=native option is not given when building on Apple M1. With this fix, I have confirmed that the installation is successful:

$ pip install .
Processing /Users/yoshoku/hnswlib

...

Building wheels for collected packages: hnswlib
  Building wheel for hnswlib (pyproject.toml) ... done

...

Successfully built hnswlib
Installing collected packages: hnswlib
Successfully installed hnswlib-0.6.0
$

[yurymalkov]

Thanks!