Infer python version from Makefile.envs in PyO3

[ryanking13]

Instead of hardcoding the Python version, use PYO3_CROSS_PYTHON_VERSION env variable, which PyO3 uses to find the correct Python include/lib paths.

Also removed pyo3_config.ini file. Otherwise, the config file always take precedence.

[ryanking13]

It isn't working, but at least I found that integration tests are useful enough to detect this kind or errors :) Let's see if I can fix it.

[ryanking13]

It is working now. I also checked it in pyodide/pyodide in my fork ryanking13/pyodide@be7e588

[hoodmane]

What about $(CPYTHONINSTALL)/lib/python$(PYMAJOR).$(PYMINOR)/?

[ryanking13]

We don't have that directory in our xbuildenv now. Normally sysconfigdata would be placed in that directory but we don't vendor lib/python3.X.Y/... part in the xbuildenv and only store sysconfigdata in the top-level directory.

xbuildenv/pyodide-root$ ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/ /' -e 's/-/|/'
 .
 |-cpython
 |---installs
 |-----python-3.12.1 (this is CPYTHONINSTALL)
 |-------include
 |---------python3.12
 |-----------cpython
 |-----------internal
 |-------sysconfigdata
 |---------__pycache__

Maybe we can change the path in the xbuildenv, but for now the sysconfigdata directory works like a directory where first-party libraries are stored.

[hoodmane]

Thanks!

[ryanking13]

Thanks for the review!