Changing libvlc_video_take_snapshot prototype

So that it takes a const char* as the filename parameter.
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

include/vlc/libvlc.h

@@ -1065,7 +1065,7 @@ VLC_PUBLIC_API void libvlc_video_set_track( libvlc_media_player_t *, int, libvlc
  * \param i_height the snapshot's height
  * \param p_e an initialized exception pointer
  */
-VLC_PUBLIC_API void libvlc_video_take_snapshot( libvlc_media_player_t *, char *,unsigned int, unsigned int, libvlc_exception_t * );
+VLC_PUBLIC_API void libvlc_video_take_snapshot( libvlc_media_player_t *, const char *,unsigned int, unsigned int, libvlc_exception_t * );
 
 /**
  * Resize the current video output window.

src/control/video.c

@@ -104,7 +104,7 @@ void libvlc_toggle_fullscreen( libvlc_media_player_t *p_mi,
 }
 
 void
-libvlc_video_take_snapshot( libvlc_media_player_t *p_mi, char *psz_filepath,
+libvlc_video_take_snapshot( libvlc_media_player_t *p_mi, const char *psz_filepath,
         unsigned int i_width, unsigned int i_height, libvlc_exception_t *p_e )
 {
     vout_thread_t *p_vout = GetVout( p_mi, p_e );