Use std:: on symbols declared in C++-style C headers.

src/platform.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 26 matching lines @@
 // the platform dependent classes could have been implemented using abstract
 // superclasses with virtual methods and having specializations for each
 // platform. This design was rejected because it was more complicated and
 // slower. It would require factory methods for selecting the right
 // implementation and the overhead of virtual methods for performance
 // sensitive like mutex locking/unlocking.
 
 #ifndef V8_PLATFORM_H_
 #define V8_PLATFORM_H_
 
-#include <cstdarg>
+#include <stdarg.h>
 
 #include "platform/mutex.h"
 #include "platform/semaphore.h"
 #include "utils.h"
 #include "v8globals.h"
 
 #ifdef __sun
 # ifndef signbit
 namespace std {
 int signbit(double x);
@@ skipping 24 matching lines @@
   };
 #else
   intgr = static_cast<int>(flt + 0.5);
   if ((intgr & 1) != 0 && intgr - flt == 0.5) {
     // If the number is halfway between two integers, round to the even one.
     intgr--;
   }
 #endif
   return intgr;
 }
-
 #endif  // _MSC_VER < 1800
 
 #endif  // V8_CC_MSVC
 
 namespace v8 {
 namespace internal {
 
 double modulo(double x, double y);
 
 // Custom implementation of math functions.
@@ skipping 508 matching lines @@
   char name_[kMaxThreadNameLength];
   int stack_size_;
   Semaphore* start_semaphore_;
 
   DISALLOW_COPY_AND_ASSIGN(Thread);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_