message: Use sched_yield when sleeping with msecs == 0
diff: @@ -249,12 +249,16 @@ pub unsafe extern "C" fn pte_osThreadCheckCancel(handle: pte_osThreadHandle) ->
  #[no_mangle]
  pub unsafe extern "C" fn pte_osThreadSleep(msecs: c_uint) {
  + if msecs == 0 {
  + Sys::sched_yield();
  + } else {
  let tm = timespec {
  tv_sec: msecs as i64 / 1000,
  tv_nsec: (msecs % 1000) as i64 * 1000000,
  };
  Sys::nanosleep(&tm, ptr::null_mut());
  }
  +}
  #[no_mangle]
  pub unsafe extern "C" fn pte_osThreadGetHandle() -> pte_osThreadHandle {
  