cargo wasix cannot find the rustc executable

[twitchax]

When building / running for the first time on Windows, the downloaded toolchain cannot be found.

$ cargo wasix build --release
Finding latest release... (https://api.github.com/repos/wasix-org/rust/releases/latest)...
Toolchain path C:\Users\twitc\AppData\Roaming\cargo-wasix\toolchains\x86_64-pc-windows-msvc_v2023-05-26.1 already exists - deleting existing files!
Downloading sysroot from url 'https://github.com/wasix-org/rust/releases/download/v2023-05-26.1/wasix-libc.tar.gz'...
Extracting...
Downloading Rust toolchain from url 'https://github.com/wasix-org/rust/releases/download/v2023-05-26.1/rust-toolchain-x86_64-pc-windows-msvc.tar.gz'...
Extracting...
Downloaded toolchain x86_64-pc-windows-msvc to C:\Users\twitc\AppData\Roaming\cargo-wasix\toolchains\x86_64-pc-windows-msvc_v2023-05-26.1\rust
Activating rustup toolchain wasix at C:\Users\twitc\AppData\Roaming\cargo-wasix\toolchains\x86_64-pc-windows-msvc_v2023-05-26.1\rust...
error: Invalid toolchain directory: rustc executable not found at C:\Users\twitc\AppData\Roaming\cargo-wasix\toolchains\x86_64-pc-windows-msvc_v2023-05-26.1\rust\bin/rustc

The binary is present, so it seems like wasix may be looking for exactly rustc instead of rustc.exe?