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

src/platform-linux.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 97 matching lines @@
 #endif
 #endif
 #undef GCC_VERSION
 }
 
 #endif  // def __arm__
 
 
 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 t->tm_zone;
 }
 
 
 double OS::LocalTimeOffset() {
   time_t tv = time(NULL);
   struct tm* t = localtime(&tv);
   // tm_gmtoff includes any daylight savings offset, so subtract it.
@@ skipping 306 matching lines @@
 bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
   return munmap(base, size) == 0;
 }
 
 
 bool VirtualMemory::HasLazyCommits() {
   return true;
 }
 
 } }  // namespace v8::internal