message: more general update
diff: @@ -12,7 +12,6 @@ use core::TargetKind;
  use super::{Context, Kind, Unit};
  use super::context::OutputFile;
  use util::{internal, CargoResult, ProcessBuilder};
  -use std::sync::Arc;
  use std::path::PathBuf;
  use serde_json;
  use semver;
  @@ -123,7 +122,7 @@ impl BuildPlan {
  &mut self,
  invocation_name: &str,
  cmd: &ProcessBuilder,
  - outputs: &Arc<Vec<OutputFile>>,
  + outputs: &[OutputFile],
  ) -> CargoResult<()> {
  let id = self.invocation_map[invocation_name];
  let invocation = self.plan
  