message: Fix unused import warning.
diff: @@ -131,8 +131,6 @@ fn ctrl_c_kills_everyone() {
  #[cfg(unix)]
  fn ctrl_c(child: &mut Child) {
  - use libc;
  -
  let r = unsafe { libc::kill(-(child.id() as i32), libc::SIGINT) };
  if r < 0 {
  panic!("failed to kill: {}", io::Error::last_os_error());
  