Making signal API real-time signal aware

changelog/2451.changed.md

@@ -0,0 +1,4 @@
+This pull request adds a new enum **SignalValue** that allows specifying both standard signals and real-time signals. For most functions, a new "real-time signal aware" version was added (for instance, for **sigaction()**, the new function is called **rt_sigaction()**). However, there are two significant changes:
+
+* Turning **SigSet** into iterator now returns real-time signal aware **SignalSetIter** instead of the old **SigSetIter**
+* The **signal** field of the **SigevSignal** and **SigevThreadId** structs is now of real-time signal aware type **SignalValue** instead of the old **Signal** type

src/sys/aio.rs

@@ -1173,7 +1173,7 @@ pub fn aio_suspend(
 ///     0,      // priority
 ///     SigevNotify::SigevNone
 /// ));
-/// let sev = SigevNotify::SigevSignal { signal: Signal::SIGUSR2, si_value: 0 };
+/// let sev = SigevNotify::SigevSignal { signal: SignalValue::Standard(Signal::SIGUSR2), si_value: 0 };
 /// lio_listio(LioMode::LIO_NOWAIT, &mut[aiow.as_mut()], sev).unwrap();
 /// while !SIGNALED.load(Ordering::Relaxed) {
 ///     thread::sleep(time::Duration::from_millis(10));