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

src/platform-posix.cc

 // 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 278 matching lines @@
 #else
 #error Unsupported host architecture.
 #endif
 }
 
 
 // ----------------------------------------------------------------------------
 // Math functions
 
 double modulo(double x, double y) {
-  return fmod(x, y);
+  return std::fmod(x, y);
 }
 
 
 #define UNARY_MATH_FUNCTION(name, generator)             \
 static UnaryMathFunction fast_##name##_function = NULL;  \
 void init_fast_##name##_function() {                     \
   fast_##name##_function = generator;                    \
 }                                                        \
 double fast_##name(double x) {                           \
   return (*fast_##name##_function)(x);                   \
@@ skipping 37 matching lines @@
 }
 
 
 double OS::TimeCurrentMillis() {
   return Time::Now().ToJsTime();
 }
 
 
 double OS::DaylightSavingsOffset(double time) {
   if (std::isnan(time)) return nan_value();
-  time_t tv = static_cast<time_t>(floor(time/msPerSecond));
+  time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
   struct tm* t = localtime(&tv);
   if (NULL == t) return nan_value();
   return t->tm_isdst > 0 ? 3600 * msPerSecond : 0;
 }
 
 
 int OS::GetLastError() {
   return errno;
 }
 
@@ skipping 408 matching lines @@
 
 void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
   pthread_key_t pthread_key = LocalKeyToPthreadKey(key);
   int result = pthread_setspecific(pthread_key, value);
   ASSERT_EQ(0, result);
   USE(result);
 }
 
 
 } }  // namespace v8::internal