message: Set required clap parameter.
diff: @@ -801,6 +801,7 @@ impl<M: Measurement> Criterion<M> {
  .value_name("baselines")
  .requires("compare")
  .require_value_delimiter(true)
  + .use_value_delimiter(true)
  .help("Limit the baselines used in tabulated results.")
  .help(""))
  .arg(Arg::new("compare-threshold")
  