v4l2: use V4L2_FMT_FLAG_EMULATED only if it is defined

V4L2_FMT_FLAG_EMULATED was added in 2.6.32.

libavdevice/v4l2.c

@@ -316,10 +316,12 @@ static void list_formats(AVFormatContext *ctx, int fd, int type)
             continue;
         }
 
+#ifdef V4L2_FMT_FLAG_EMULATED
         if (vfd.flags & V4L2_FMT_FLAG_EMULATED) {
             av_log(ctx, AV_LOG_WARNING, "%s", "Emulated");
             continue;
         }
+#endif
 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
         list_framesizes(ctx, fd, vfd.pixelformat);
 #endif