libvpx: Add VP9 decoder.

source/libvpx/vp9/common/vp9_rtcd.c

+/*
+ *  Copyright (c) 2011 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#include "vpx_config.h"
+#define RTCD_C
+#include "vp9_rtcd.h"
+#include "vpx_ports/vpx_once.h"
+
+extern void vpx_scale_rtcd(void);
+
+void vp9_rtcd()
+{
+    vpx_scale_rtcd();
+    once(setup_rtcd_internal);
+}