We're preparing to release rustup 1.24, which includes this PR: rust-lang/rustup#2695

As the PR and linked bugs discuss, we're trying to get ahead of interactive users accidentally installing toolchains when they should add targets instead. cross probably wants to keep installing toolchains: you should add --force-non-host to the command line for both rustup toolchain install and rustup update [these are the same command under the hood].

Don't add it until we release though, since it isn't accepted by rustup 1.23 and below, and will error if used right now.

Thanks!