SDL_mixer is now entirely contained in Music.cpp.

This meant making the track vectors static, but that's kind of what we do with musicclass anyway?

In any case, this will make the transition to FAudio MUCH less invasive.

desktop_version/src/Music.cpp

@@ -15,6 +15,24 @@
 
 /* Begin SDL_mixer wrapper */
 
+#include <SDL_mixer.h>
+#include <vector>
+
+class MusicTrack
+{
+public:
+    MusicTrack(SDL_RWops *rw);
+    Mix_Music *m_music;
+    bool m_isValid;
+};
+
+class SoundTrack
+{
+public:
+    SoundTrack(const char* fileName);
+    Mix_Chunk *sound;
+};
+
 MusicTrack::MusicTrack(SDL_RWops *rw)
 {
     m_music = Mix_LoadMUS_RW(rw, 1);
@@ -50,6 +68,9 @@ SoundTrack::SoundTrack(const char* fileName)
     }
 }
 
+static std::vector<MusicTrack> musicTracks;
+static std::vector<SoundTrack> soundTracks;
+
 /* End SDL_mixer wrapper */
 
 musicclass::musicclass(void)