Bug fix for stack overflow error that can occur when calling QCoreApplication::processEvents() and not guarding against recursion on calling parent function.

src/drivers/Qt/ConsoleWindow.cpp

@@ -4285,9 +4285,18 @@ void consoleWin_t::transferVideoBuffer(void)
 
 void consoleWin_t::emuFrameFinish(void)
 {
+	static bool eventProcessingInProg = false;
+
+	if ( eventProcessingInProg )
+	{   // Prevent recursion as processEvents function can double back on us
+		return;
+	}
+	eventProcessingInProg = true;
 	// Process all events before attempting to render viewport
 	QCoreApplication::processEvents();
 
+	eventProcessingInProg = false;
+
 	// Update Input Devices
 	FCEUD_UpdateInput();
 	
@@ -4298,9 +4307,18 @@ void consoleWin_t::emuFrameFinish(void)
 
 void consoleWin_t::updatePeriodic(void)
 {
+	static bool eventProcessingInProg = false;
+
+	if ( eventProcessingInProg )
+	{   // Prevent recursion as processEvents function can double back on us
+		return;
+	}
+	eventProcessingInProg = true;
 	// Process all events before attempting to render viewport
 	QCoreApplication::processEvents();
 
+	eventProcessingInProg = false;
+
 	// Update Input Devices
 	FCEUD_UpdateInput();