ENH: Add -Werror to CI (or at least show warnings)

[WillAyd]

Feature Type

• Adding new functionality to pandas

• Changing existing functionality in pandas

• Removing existing functionality in pandas

Problem Description

Not sure if this was lost along the way but we originally did this in #38087

After #55151 was merged both @jbrockmendel and @rhshadrach had a lot of compiler warnings pop up. Both are on macOS, so I would have expected the macOS jobs to fail or at the very least still show compiler warnings, but am not seeing anything

@lithomas1 you may have already looked into this

Feature Description

Make sure compiler errors cause CI failures

Alternative Solutions

n/a

Additional Context

No response

[mroeschke]

Looks like -Werror is still in our setup.py, but not in our meson.build.

Also appears the debugging symbols (when requested) and MacOS specific Cython flags are missing too, but not too sure how necessary those are still to keep

[WillAyd]

Good callouts. The debugging symbols should be replaced with --config-settings=setup-args="-Dbuildtype=debug" during the pip install and meson-python should handle that correctly. Not sure about the macOS stuff but that is mostly for wheel building, not necessarily our CI

Haven't tested but I assume something like --config-settings=setup-args="--werror" should work for meson in CI

https://meson-python.readthedocs.io/en/latest/how-to-guides/meson-args.html