Incorrect CBC solver build used with macOS on ARM 64

[peterjc]

Details for the issue

I'm trying to use snakemake on macOS on the Apple ARM M3 chip, installed via conda. It failed snakemake/snakemake#3007 with the following error from pulp:

OSError: [Errno 86] Bad CPU type in executable: '/Users/peterjc/miniforge3/envs/snakemake-testing/lib/python3.12/site-packages/pulp/solverdir/cbc/osx/64/cbc'

I've looked at the conda-forge packaging of pulp and this currently uses the cbc binaries you provide conda-forge/pulp-feedstock#40 rather than compiling them or handling this as an explicit external dependency. See also #740 for a similar discussion about packaging. Currently you only have x64 binaries for macOS:

https://github.com/coin-or/pulp/tree/v2.1/pulp/solverdir/cbc/osx
https://github.com/coin-or/pulp/tree/master/pulp/solverdir/cbc/osx

This seems to be the Apple equivalent of #672 and #685 for Linux aarch64, which added Linux ARM binaries and will be a welcome addition to the next release. Can the same be done for macOS ARM too please?

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What operating system are you using?

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I'm using python version:

• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
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I installed PuLP via:

• pypi (python -m pip install pulp)
• github (python -m pip install -U git+https://github.com/coin-or/pulp)
• Other: conda-forge

Did you also

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• Searched for an existing similar issue: https://github.com/coin-or/pulp/issues?utf8=%E2%9C%93&q=is%3Aissue%20