message: Ensure rustc-echo-wrapper works with an overridden build.target-dir
diff: @@ -1209,7 +1209,7 @@ pub trait TestEnv: Sized {
  .current_dir(&paths::root())
  .env("HOME", paths::home())
  .env("CARGO_HOME", paths::home().join(".cargo"))
  - .env("__CARGO_TEST_ROOT", paths::root())
  + .env("__CARGO_TEST_ROOT", paths::global_root())
  // Force Cargo to think it's on the stable channel for all tests, this
  // should hopefully not surprise us as we add cargo features over time and
  // cargo rides the trains.
  