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

src/platform-cygwin.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 35 matching lines @@
 #include "v8threads.h"
 #include "vm-state-inl.h"
 #include "win32-headers.h"
 
 namespace v8 {
 namespace internal {
 
 
 const char* OS::LocalTimezone(double time) {
   if (std::isnan(time)) return "";
-  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 "";
   return tzname[0];  // The location of the timezone string on Cygwin.
 }
 
 
 double OS::LocalTimeOffset() {
   // On Cygwin, struct tm does not contain a tm_gmtoff field.
   time_t utc = time(NULL);
   ASSERT(utc != -1);
@@ skipping 281 matching lines @@
   return VirtualFree(base, 0, MEM_RELEASE) != 0;
 }
 
 
 bool VirtualMemory::HasLazyCommits() {
   // TODO(alph): implement for the platform.
   return false;
 }
 
 } }  // namespace v8::internal