Describe the issue linked to the documentation

Environment variables CFLAGS, CXXFLAGS, CXXFLAGS mentioned here:
https://scikit-learn.org/dev/developers/advanced_installation.html#compiler-macos:~:text=Set%20the%20following%20environment%20variables%3A
may be for Intel-based Macs only.

So when trying to do this:

make clean
pip install --editable . \
    --verbose --no-build-isolation \
    --config-settings editable-verbose=true

I got ../../meson.build:1:0: ERROR: Compiler /usr/bin/clang cannot compile programs.

The reason being that Homebrew installed libomp here: /opt/homebrew/opt/libomp and not here/usr/local/opt/libomp/.

Suggest a potential alternative/fix

Modify the env variables that I mentioned above to the right path to libomp for M2 macs.

Please note:

• I'm not sure if the variables should be updated or have the two mac versions (Intel vs M1/M2).
• I didn't test that all works for an Intel mac.
• Modifying the variables to the correct path, I was able to make the new environment.