spark audio: add support for channel specific volume

libspark/audio_lib.h

@@ -56,6 +56,9 @@ class cAudio
 
 		int do_mute(bool enable, bool remember);
 		void setBypassMode(bool disable);
+#ifdef MARTII
+		int percent;
+#endif
 	public:
 		/* construct & destruct */
 		cAudio(void *, void *, void *);
@@ -91,6 +94,10 @@ class cAudio
 		void SetSpdifDD(bool enable);
 		void ScheduleMute(bool On);
 		void EnableAnalogOut(bool enable);
+#ifdef MARTII
+		int getPercent(void);
+		int setPercent(int perc);
+#endif
 };
 
 #endif