lib: return the same object in libvlc_media_retain()

include/vlc/libvlc_media.h

@@ -413,8 +413,9 @@ LIBVLC_API void libvlc_media_add_option_flag(
  * media descriptor object.
  *
  * \param p_md the media descriptor
+ * \return the same object
  */
-LIBVLC_API void libvlc_media_retain( libvlc_media_t *p_md );
+LIBVLC_API libvlc_media_t *libvlc_media_retain( libvlc_media_t *p_md );
 
 /**
  * Decrement the reference count of a media descriptor object. If the

lib/media.c

@@ -641,10 +641,11 @@ void libvlc_media_release( libvlc_media_t *p_md )
 }
 
 // Retain a media descriptor object
-void libvlc_media_retain( libvlc_media_t *p_md )
+libvlc_media_t *libvlc_media_retain( libvlc_media_t *p_md )
 {
     assert (p_md);
     vlc_atomic_rc_inc( &p_md->rc );
+    return p_md;
 }
 
 // Duplicate a media descriptor object