message: Ignore rustc_args
diff: @@ -59,7 +59,10 @@ pub fn build_doc(name: &str, vers: Option<&str>, target: Option<&str>) -> CargoR
  release: false,
  message_format: ops::MessageFormat::Human,
  filter: ops::CompileFilter::new(true, &[], &[], &[], &[]),
  - target_rustc_args: metadata.rustc_args.as_ref().map(Vec::as_slice),
  + // FIXME: cargo is ignoring target_rustdoc_args if rustc_args set.
  + // I believe this is expected behavior when building docs but I am not sure.
  + // This needs to be investigated.
  + target_rustc_args: None,
  target_rustdoc_args: metadata.rustdoc_args.as_ref().map(Vec::as_slice),
  };
  