Add build script for Windows on ARM64

[Harishmcw]

This PR adds build_steps_win_arm64.bat, a script that automates the process of building OpenBLAS and packaging it into a SciPy-compatible wheel on Windows ARM64. It compiles OpenBLAS using the ARM64 native command prompt, prepares the necessary files, and generates a wheel for seamless integration with SciPy.

• I updated the version in pyproject.toml and made sure it matches git describe --tags --abbrev=8 in OpenBLAS at the OPENBLAS_COMMIT

[mattip]

Shouldn't the BUILD_BITS be used to define a prefix/suffix in the exported function names? Or am I missing where this is done?

[Harishmcw]

Shouldn't the BUILD_BITS be used to define a prefix/suffix in the exported function names? Or am I missing where this is done?

The suffix/prefix on exported symbols is determined based on the if_bits variable in the build_openblas.sh script, while the build_bits variable is used for configuring the OpenBLAS build.

If INTERFACE64 is set to 1, if_bits is assigned 64; otherwise, it defaults to 32. Since INTERFACE64 is not used here, if_bits remains 32, resulting in only the prefix scipy_ being added without any suffixes

[mattip]

Ahh, I see. NumPy uses the 64-bit interfaces, so I guess more work will be needed to produce those wheels.

[mattip]

Thanks.