sout_MuxGetStream: fix prototype, sign warning

include/vlc_sout.h

@@ -158,7 +158,7 @@ VLC_API sout_input_t * sout_MuxAddStream( sout_mux_t *, es_format_t * ) VLC_USED
 VLC_API void sout_MuxDeleteStream( sout_mux_t *, sout_input_t * );
 VLC_API void sout_MuxDelete( sout_mux_t * );
 VLC_API int sout_MuxSendBuffer( sout_mux_t *, sout_input_t  *, block_t * );
-VLC_API int sout_MuxGetStream(sout_mux_t *, int , mtime_t *);
+VLC_API int sout_MuxGetStream(sout_mux_t *, unsigned, mtime_t *);
 
 static inline int sout_MuxControl( sout_mux_t *p_mux, int i_query, ... )
 {

src/stream_output/stream_output.c

@@ -548,7 +548,7 @@ int sout_MuxSendBuffer( sout_mux_t *p_mux, sout_input_t *p_input,
 /*****************************************************************************
  * sout_MuxGetStream: find stream to be muxed
  *****************************************************************************/
-int sout_MuxGetStream( sout_mux_t *p_mux, int i_blocks, mtime_t *pi_dts )
+int sout_MuxGetStream( sout_mux_t *p_mux, unsigned i_blocks, mtime_t *pi_dts )
 {
     mtime_t i_dts = 0;
     int     i_stream = -1;