libvpx: Pull from upstream

source/libvpx/args.h

 /*
  *  Copyright (c) 2010 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.
  */
 
 
 #ifndef ARGS_H_
 #define ARGS_H_
 #include <stdio.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct arg {
   char                 **argv;
   const char            *name;
   const char            *val;
   unsigned int           argv_step;
   const struct arg_def  *def;
 };
 
 struct arg_enum_list {
   const char *name;
@@ skipping 15 matching lines @@
 struct arg arg_init(char **argv);
 int arg_match(struct arg *arg_, const struct arg_def *def, char **argv);
 const char *arg_next(struct arg *arg);
 void arg_show_usage(FILE *fp, const struct arg_def *const *defs);
 char **argv_dup(int argc, const char **argv);
 
 unsigned int arg_parse_uint(const struct arg *arg);
 int arg_parse_int(const struct arg *arg);
 struct vpx_rational arg_parse_rational(const struct arg *arg);
 int arg_parse_enum_or_int(const struct arg *arg);
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
 #endif  // ARGS_H_