3 If you'd like to build for a target that is not yet supported by `rustc`, you can use a
4 "custom target specification" to define a target. These target specification files
5 are JSON. To see the JSON for the host target, you can run:
8 $ rustc +nightly -Z unstable-options --print target-spec-json
11 To see it for a different target, add the `--target` flag:
14 $ rustc +nightly -Z unstable-options --target=wasm32-unknown-unknown --print target-spec-json
17 To use a custom target, see [`xargo`](https://github.com/japaric/xargo).