message: Add sigismember
diff: @@ -131,9 +131,21 @@ pub extern "C" fn siginterrupt(sig: c_int, flag: c_int) -> c_int {
  unimplemented!();
  }
  -// #[no_mangle]
  +#[no_mangle]
  pub extern "C" fn sigismember(set: *const sigset_t, signo: c_int) -> c_int {
  - unimplemented!();
  + if signo <= 0 || signo as usize > NSIG {
  + unsafe {
  + platform::errno = errno::EINVAL;
  + }
  + return -1;
  + }
  +
  + if let Some(set) = unsafe { (set as *mut SigSet).as_mut() } {
  + if set.contains(signo as usize - 1) {
  + return 1;
  + }
  + }
  + 0
  }
  extern "C" {
  