message: Limit the number of build threads
diff: @@ -457,7 +457,7 @@ impl RustwideBuilder {
  if let Some(package_rustdoc_args) = &metadata.rustdoc_args {
  rustdoc_flags.append(&mut package_rustdoc_args.iter().map(|s| s.to_owned()).collect());
  }
  - let mut cargo_args = vec!["doc", "--lib", "--no-deps"];
  + let mut cargo_args = vec!["doc", "--lib", "--no-deps", "-j2"];
  if target != HOST_TARGET {
  // If the explicit target is not a tier one target, we need to install it.
  if !TARGETS.contains(&target) {
  