Replace math.h with cmath

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 186 matching lines @@
 int64_t OS::Ticks() {
   // gettimeofday has microsecond resolution.
   struct timeval tv;
   if (gettimeofday(&tv, NULL) < 0)
     return 0;
   return (static_cast<int64_t>(tv.tv_sec) * 1000000) + tv.tv_usec;
 }
 
 
 double OS::DaylightSavingsOffset(double time) {
-  if (isnan(time)) return nan_value();
+  if (std::isnan(time)) return nan_value();
   time_t tv = static_cast<time_t>(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 345 matching lines @@
   return ntohl(value);
 }
 
 
 Socket* OS::CreateSocket() {
   return new POSIXSocket();
 }
 
 
 } }  // namespace v8::internal