message: inform the user when and where we are creating a cache dir
diff: @@ -149,6 +149,7 @@ fn setup(ask_user: bool) {
  let dirs = directories::ProjectDirs::from("miri", "miri", "miri").unwrap();
  let dir = dirs.cache_dir();
  if !dir.exists() {
  + println!("Creating `{}` and using it for miri's build of libstd", dir.display());
  fs::create_dir_all(&dir).unwrap();
  }
  // The interesting bit: Xargo.toml
  