message: set RUSTC_DEBUG_ASSERTIONS for when we are in bootstrap
diff: @@ -310,17 +310,21 @@ version = "0.0.0"
  path = "lib.rs"
  "#).unwrap();
  File::create(dir.join("lib.rs")).unwrap();
  - // Run xargo.
  + // Prepare xargo invocation.
  let target = get_arg_flag_value("--target");
  let print_env = !ask_user && has_arg_flag("--env"); // whether we just print the necessary environment variable
  let mut command = xargo();
  - command.arg("build").arg("-q")
  - .current_dir(&dir)
  - .env("RUSTFLAGS", miri::miri_default_args().join(" "))
  - .env("XARGO_HOME", dir.to_str().unwrap());
  + command.arg("build").arg("-q");
  + command.current_dir(&dir);
  + command.env("RUSTFLAGS", miri::miri_default_args().join(" "));
  + command.env("XARGO_HOME", dir.to_str().unwrap());
  + // In bootstrap, make sure we don't get debug assertons into our libstd.
  + command.env("RUSTC_DEBUG_ASSERTIONS", "false");
  + // Handle target flag.
  if let Some(ref target) = target {
  command.arg("--target").arg(&target);
  }
  + // Finally run it!
  if !command.status()
  .expect("failed to run xargo")
  .success()
  