InputStream: convert to class

src/playlist/CloseSongEnumerator.hxx

@@ -23,7 +23,7 @@
 #include "SongEnumerator.hxx"
 #include "Compiler.h"
 
-struct InputStream;
+class InputStream;
 
 /**
  * A #SongEnumerator wrapper that closes an #InputStream automatically

src/playlist/PlaylistPlugin.hxx

@@ -21,7 +21,7 @@
 #define MPD_PLAYLIST_PLUGIN_HXX
 
 struct config_param;
-struct InputStream;
+class InputStream;
 struct Tag;
 class Mutex;
 class Cond;

src/playlist/PlaylistRegistry.hxx

@@ -23,7 +23,7 @@
 class Mutex;
 class Cond;
 class SongEnumerator;
-struct InputStream;
+class InputStream;
 
 extern const struct playlist_plugin *const playlist_plugins[];