OK, I don't think I need to file a wine bug after all, I can't even repro the issue locally. But I may wind up filing an issue about how cibuildwheel finds paths when run under Wine. I know that's a borderline [REDACTED] thing to do, but I have good reasons!
Amazingly, `uv tool run --from build pyproject-build` gets as far as bootstrapping all of Rustup and starts building Rust code before hitting issues in dependency crates.