New comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/46117#issuecomment-1728605077

Comment:
> 1. Would it make sense to set `-Csetup-args=--cross-file=${XBPS_WRAPPERDIR}/meson/xbps_meson.cross` in the `python3-pep517` style (only if using meson helper), or is that "too much magic"?

I think adding this argument to the PEP517 style is reasonable. It shouldn't be "too much magic" because it confines its manipulations to the actual build functions where this kind of thing is expected.

> 2. Would it make sense to place the configuration for numpy and
>    pythran in `xbps_meson.cross` itself? I assume unused properties are harmless.

This would probably better in the numpy build helper, which can check if the meson helper is also enabled and write a second cross file. We can then add another check in the PEP517 helper to automatically add the second file to the build arguments.

> 3. The helper seems to be called several times at different stages, so the crossfile would be written several times, maybe with different content? Could this be an issue in some case?

I thought about this and decided to follow the precedent of the qmake helper, but we could also add a check to avoid writing the file if it already exists. I'm not sure it matters.

While I'm inclined to adopt the numpy and pep517 improvements, let's consider those in a separate PR after this more general change is merged.