message: avoid setting both RUSTC and RUSTC_WRAPPER
diff: @@ -638,6 +638,14 @@ fn phase_cargo_miri(mut args: env::Args) {
  );
  }
  cmd.env("RUSTC_WRAPPER", &cargo_miri_path);
  + // Having both `RUSTC_WRAPPER` and `RUSTC` set does some odd things, so let's avoid that.
  + // See <https://github.com/rust-lang/miri/issues/2238>.
  + if env::var_os("RUSTC").is_some() && env::var_os("MIRI").is_none() {
  + println!(
  + "WARNING: Ignoring `RUSTC` environment variable; set `MIRI` if you want to control the binary used as the driver."
  + );
  + }
  + cmd.env_remove("RUSTC");
  let runner_env_name =
  |triple: &str| format!("CARGO_TARGET_{}_RUNNER", triple.to_uppercase().replace('-', "_"));
  