Don't call set_notification_runloop on Mac OS 10.7 or later version

Author: ChunMinChang

src/backend/mod.rs

@@ -1955,7 +1955,15 @@ impl AudioUnitContext {
 
 impl ContextOps for AudioUnitContext {
     fn init(_context_name: Option<&CStr>) -> Result<Context> {
-        set_notification_runloop();
+        // set_notification_runloop (kAudioHardwarePropertyRunLoop) doesn't work since 10.7.
+        if let Ok(v) = os_version() {
+            if let Ok(v) = v.parse::<f32>() {
+                const MAC_OS_LION: f32 = 10.7;
+                if v < MAC_OS_LION {
+                    set_notification_runloop();
+                }
+            }
+        }
         let ctx = Box::new(AudioUnitContext::new());
         Ok(unsafe { Context::from_ptr(Box::into_raw(ctx) as *mut _) })
     }