Closed issue by tranzystorek-io on void-packages repository

https://github.com/void-linux/void-packages/issues/42100

Description:
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In `rust-bootstrap` and `cargo-bootstrap`, the `distfile` variable uses `RUST_TARGET` to determine which artifact to fetch, but RUST_TARGET is unset per our policy. I tried switching to other variables like `XBPS_RUST_TARGET`, but it seems especially `distfiles` is set early, before profiles have been sourced etc.