Ship stub files with librt

[JukkaL]

To allow IDEs and other type checkers to type check code that uses librt, we should ship stub files in the wheels, using PEP 561. We can probably just copy the stub files from mypy/typeshed/stubs/librt when syncing code from the mypy repository to librt.

cc @ilevkivskyi

[JukkaL]

I guess mypy should always use the librt stubs under mypy/typeshed -- this would be strictly for third-party tool support.

[ilevkivskyi]

TBH I am not a big expert in PEP 561. I can take a look at it this evening. Otherwise @emmatyping may also know what is the recommended way to include stubs for extension modules.

[ilevkivskyi]

@JukkaL Hm, I updated the sync script to also pull the stubs from mypy and updated pyproject.toml to include them in the wheel (and it seems to work, at least for PyCharm), see mypyc/librt#14. But:

• The sync also includes base64, is it fine to publish it now?
• It looks like there was some change to compile flags that broke pyodide builds

  emcc: error: passing any of -msse, -msse2, -msse3, -mssse3, -msse4.1, -msse4.2, -msse4, -mavx, -mfpu=neon flags also requires passing -msimd128 (or -mrelaxed-simd)!
  error: command '/home/runner/work/librt/librt/.pyodide_build/pywasmcross_symlinks/cc' failed with exit code 1
  

[ilevkivskyi]

OK, I fixed the WASM wheels in mypyc/librt#14. If this looks OK, I will "backport" this fix to mypy.

[emmatyping]

Otherwise @emmatyping may also know what is the recommended way to include stubs for extension modules.

In general, I'd recommend putting the stub for each extension module next to it and add a py.typed file at the root. I think that is what you were planning?

[ilevkivskyi]

@emmatyping

In general, I'd recommend putting the stub for each extension module next to it and add a py.typed file at the root. I think that is what you were planning?

Yes, this is exactly what I am doing in mypyc/librt#14