message: Change to enumerate implementation
  Only printing an empty line after the first target output is changed to
  use the `enumerate` method on an Iterator with a non-zero index.
  I could not get the `drop_println` macro to compile. Something about the
  `shell` missing. The standard library `println` macro seems work fine.
diff: @@ -308,14 +308,16 @@ pub fn print<'a>(
  if kinds.is_empty() {
  kinds.push(CompileKind::Host);
  }
  - let mut print_empty_line = false;
  - for kind in kinds {
  + for (index, kind) in kinds.iter().enumerate() {
  + if index != 0 {
  + println!();
  + }
  let rustflags = env_args(
  config,
  &build_config.requested_kinds,
  &rustc.host,
  None,
  - kind,
  + *kind,
  "RUSTFLAGS",
  )?;
  let mut process = rustc.process();
  @@ -332,11 +334,6 @@ pub fn print<'a>(
  let output = process.exec_with_output()?;
  let stdout = std::io::stdout();
  let mut lock = stdout.lock();
  - if print_empty_line {
  - writeln!(lock)?;
  - } else {
  - print_empty_line = true;
  - }
  lock.write_all(&output.stdout)?;
  drop(lock);
  }
  