message: Document that most targets are cross-compiled
diff: This approach can be helpful if you need dependencies for building the library, but not for building the documentation.
  </p>
  + <h4 id="cross-compiling">Cross-compiling</h4>
  + <p>
  + All targets other than <code>x86_64-unknown-linux-gnu</code> are cross-compiled. For implementation reasons, this is unlikely to change for the foreseeable future.
  + </p>
  +
  <p>
  You can configure how your crate is built by adding <a href="metadata">package metadata</a> to your <code>Cargo.toml</code>, e.g.:
  {% filter dedent -%}
  