message: Make multiple threads to try to join a thread while it is still running.
diff: @@ -10,6 +10,8 @@ use std::thread;
  use std::{mem, ptr};
  extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
  + thread::yield_now();
  + thread::yield_now();
  ptr::null_mut()
  }
  