[WIP]: Updates for Pyodide builds after pyodide-build was unvendored

[agriyakhetarpal]

Tip

This PR is currently a work in progress and is not yet ready for review. However, feedback is welcome. The text below is a stub and will be updated with code changes.

This PR updates the Pyodide build procedure (see #1456) that is enabled with CIBW_PLATFORM: "pyodide" (or with the --platform pyodide CLI equivalent) post the changes in pyodide/pyodide#4882, where pyodide/pyodide-build was unvendored from the main Pyodide repository to accommodate faster updates and fixes.

This means that the Pyodide version and pyodide-build are not going to be in sync going forward, and that the Pyodide xbuildenv to install must be inferred by the versions available to install by pyodide-build through a recently added pyodide xbuildenv search command, which prints out this table:

Tap to expand table

Starting new HTTPS connection (1): raw.githubusercontent.com:443
https://raw.githubusercontent.com:443 "GET /pyodide/pyodide/main/pyodide-cross-build-environments.json HTTP/11" 200 917
Version         Python          Emscripten      pyodide-build                   Compatible
----------      ----------      ----------      -------------------------       ----------
0.27.0a2        3.12.1          3.1.58          0.26.0 -                        Yes       
0.26.2          3.12.1          3.1.58          0.26.0 -                        Yes       
0.26.1          3.12.1          3.1.58          0.26.0 -                        Yes       
0.26.0          3.12.1          3.1.58          0.26.0 -                        Yes   

Alternatively, one may use pyodide xbuildenv search --all to return both compatible and non-compatible versions. This would, however, be better received as JSON (please see pyodide/pyodide-build#28).

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Additionally, in this PR, I would like to implement support for installing arbitrary Pyodide versions, or, more specifically, arbitrary Pyodide xbuildenv versions – though, only the ones that are supported for a given pyodide-build version. This could be done through an environment variable PYODIDE_XBUILDENV_VERSION (or, PYODIDE_VERSION because it's shorter) and an associated configuration variable in the schema. It would therefore be great to get the above table in machine-readable code to validate it inside cibuildwheel/pyodide.py – for which I opened pyodide/pyodide-build#26 and I'm working on that right now. The rationale behind this is that WebAssembly/Pyodide builds are already experimental anyway, and it would be useful to not tie the available Pyodide version to the cibuildwheel version – this would be helpful for downstream projects (statsmodels/statsmodels#9343, scikit-image/scikit-image#7525, scikit-learn/scikit-learn#29791, and so on) to allow testing against Pyodide alpha releases and/or for the case of reproducibility against Pyodide's older releases.

cc: @hoodmane and @ryanking13 for visibility

[agriyakhetarpal]

The Windows test failures are unrelated. I'll try to fix them later in the day, but happy to step back if someone else does it before me, or wishes to.