Build cargo-vendor from source

[dezgeg]

Since 491e5d8 rustc works on aarch64, but cargo doesn't because we depend on binary releases of cargo-vendor (https://github.com/alexcrichton/cargo-vendor/releases) but upstream doesn't provide binaries for non-x86.

[andir]

Any ideas on how to get started with this? We probably have to (semi) manually keep track of the dependencies (of one version)?

Once the first version exists we could probably refer to that as some kind of bootstrap stage to build newer versions of cargo-vendor using itself?

[dezgeg]

I've learned since that there's a tool called carnix (#31150) that would probably help here.

[dezgeg]

Fixed since #33980 was merged.