Speaker fade: use proper type

source/Common.h

@@ -23,6 +23,7 @@ enum AppMode_e
 	, MODE_DEBUG    // 6502 is paused
 	, MODE_STEPPING // 6502 is running at normal/full speed (Debugger breakpoints always active)
 	, MODE_BENCHMARK
+	, MODE_UNDEFINED	// Used in SoundCore_SetFade()
 };
 
 #define  SPEED_MIN         0

source/SoundCore.cpp

@@ -438,7 +438,7 @@ static VOID CALLBACK SoundCore_TimerFunc(HWND hwnd, UINT uMsg, UINT_PTR idEvent,
 
 void SoundCore_SetFade(eFADE FadeType)
 {
-	static int nLastMode = -1;
+	static AppMode_e nLastMode = MODE_UNDEFINED;
 
 	if(g_nAppMode == MODE_DEBUG)
 		return;