suppress the second warning

Originally committed as revision 12276 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/snow.c

@@ -2891,7 +2891,9 @@ static int get_4block_rd(SnowContext *s, int mb_x, int mb_y, int plane_index){
     const int ref_stride= s->current_picture.linesize[plane_index];
     uint8_t *dst= s->current_picture.data[plane_index];
     uint8_t *src= s-> input_picture.data[plane_index];
-    static const IDWTELEM zero_dst[4096]; //FIXME
+    //FIXME zero_dst is const but add_yblock changes dst if add is 0 (this is never the case for dst=zero_dst
+    // const has only been removed from zero_dst to suppress a warning
+    static IDWTELEM zero_dst[4096]; //FIXME
     const int b_stride = s->b_width << s->block_max_depth;
     const int w= p->width;
     const int h= p->height;