GE Debugger: Prevent hang on shutdown.

Since we're blocking the Emu thread, we can't use a hook from the Emu
thread to wake up.

The change to lifecycle callbacks caused this.

Core/Core.cpp

@@ -54,7 +54,8 @@ static std::condition_variable m_InactiveCond;
 static std::mutex m_hInactiveMutex;
 static bool singleStepPending = false;
 static int steppingCounter = 0;
-static std::set<CoreLifecycleFunc> shutdownFuncs;
+static std::set<CoreLifecycleFunc> lifecycleFuncs;
+static std::set<CoreStopRequestFunc> stopFuncs;
 static bool windowHidden = false;
 static double lastActivity = 0.0;
 static double lastKeepAwake = 0.0;
@@ -76,17 +77,24 @@ void Core_NotifyActivity() {
 }
 
 void Core_ListenLifecycle(CoreLifecycleFunc func) {
-	shutdownFuncs.insert(func);
+	lifecycleFuncs.insert(func);
 }
 
 void Core_NotifyLifecycle(CoreLifecycle stage) {
-	for (auto it = shutdownFuncs.begin(); it != shutdownFuncs.end(); ++it) {
-		(*it)(stage);
+	for (auto func : lifecycleFuncs) {
+		func(stage);
 	}
 }
 
+void Core_ListenStopRequest(CoreStopRequestFunc func) {
+	stopFuncs.insert(func);
+}
+
 void Core_Stop() {
 	Core_UpdateState(CORE_POWERDOWN);
+	for (auto func : stopFuncs) {
+		func();
+	}
 }
 
 bool Core_IsStepping() {