Message 395376 - Python tracker

>  MultiLoopChildWatcher must ensures that the event loop is awaken when it receives a signal by using signal.setwakeup(). This is done by _UnixSelectorEventLoop.add_signal_handler(). Maybe MultiLoopChildWatcher could reuse this function, rather than calling directly signal.signal().

I think this is a good idea. MultiLoopChildWatcher could use setwakeupfd with some no-op callback just to wakeup the loop.