avfilter.h, buffer.c: use const src pointer in avfilter_copy_buffer_ref_props

Signed-off-by: Roman Fietze <roman.fietze@telemotive.de>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/avfilter.h

@@ -199,7 +199,7 @@ typedef struct AVFilterBufferRef {
  * Copy properties of src to dst, without copying the actual data
  */
 attribute_deprecated
-void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src);
+void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, const AVFilterBufferRef *src);
 
 /**
  * Add a new reference to a buffer.

libavfilter/buffer.c

@@ -150,7 +150,7 @@ int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src)
     return 0;
 }
 
-void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)
+void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, const AVFilterBufferRef *src)
 {
     // copy common properties
     dst->pts             = src->pts;