Replace math.h with cmath

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 28 matching lines @@
 // 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_
 
 #ifdef __sun
 # ifndef signbit
+namespace std {
 int signbit(double x);
+}
 # endif
 #endif
 
 // GCC specific stuff
 #ifdef __GNUC__
 
 // Needed for va_list on at least MinGW and Android.
 #include <stdarg.h>
 
 #define __GNUC_VERSION__ (__GNUC__ * 10000 + __GNUC_MINOR__ * 100)
@@ skipping 667 matching lines @@
   static uint16_t HToN(uint16_t value);
   static uint16_t NToH(uint16_t value);
   static uint32_t HToN(uint32_t value);
   static uint32_t NToH(uint32_t value);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_