Support decoding 32bit sunrast images.

Fixes ticket #895.

libavcodec/sunrast.c

@@ -98,6 +98,9 @@ static int sunrast_decode_frame(AVCodecContext *avctx, void *data,
         case 24:
             avctx->pix_fmt = (type == RT_FORMAT_RGB) ? PIX_FMT_RGB24 : PIX_FMT_BGR24;
             break;
+        case 32:
+            avctx->pix_fmt = (type == RT_FORMAT_RGB) ? PIX_FMT_RGB0 : PIX_FMT_BGR0;
+            break;
         default:
             av_log(avctx, AV_LOG_ERROR, "invalid depth\n");
             return -1;