fix: build on old ffmpeg versions

src/common.h

@@ -3,3 +3,7 @@
 #include "WallpaperEngine/Core/Wallpapers/CWeb.h"
 #include "WallpaperEngine/Logging/CLog.h"
 
+// TODO: FIND A BETTER PLACE TO DO THIS? OLD_API MIGHT EXIST BUT THIS DEFINE MIGHT NOT BE DEFINED...
+#ifndef FF_API_FIFO_OLD_API
+#define 	FF_API_FIFO_OLD_API   (LIBAVUTIL_VERSION_MAJOR < 59)
+#endif