o add missing files

tools/bsnes/system/audio/audio.cpp

@@ -0,0 +1,13 @@
+#ifdef SYSTEM_CPP
+
+Audio audio;
+
+void Audio::sample(uint16 l_sample, uint16 r_sample) {
+  system.interface->audio_sample(l_sample, r_sample);
+}
+
+void Audio::init() {
+}
+
+#endif
+

tools/bsnes/system/audio/audio.hpp

@@ -0,0 +1,8 @@
+class Audio {
+public:
+  void sample(uint16 l_sample, uint16 r_sample);
+  void init();
+};
+
+extern Audio audio;
+