Fix compilation with MinGW-w64.

src/platform-win32.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 40 matching lines @@
 #ifdef __MINGW32__
 
 int localtime_s(tm* out_tm, const time_t* time) {
   tm* posix_local_time_struct = localtime(time);
   if (posix_local_time_struct == NULL) return 1;
   *out_tm = *posix_local_time_struct;
   return 0;
 }
 
 
-// Not sure this the correct interpretation of _mkgmtime
-time_t _mkgmtime(tm* timeptr) {
-  return mktime(timeptr);
-}
-
-
 int fopen_s(FILE** pFile, const char* filename, const char* mode) {
   *pFile = fopen(filename, mode);
   return *pFile != NULL ? 0 : 1;
 }
 
 
+#ifndef __MINGW64_VERSION_MAJOR
+
+// Not sure this the correct interpretation of _mkgmtime
+time_t _mkgmtime(tm* timeptr) {
+  return mktime(timeptr);
+}
+
+
 #define _TRUNCATE 0
 #define STRUNCATE 80
 
+#endif  // __MINGW64_VERSION_MAJOR
+
+
 int _vsnprintf_s(char* buffer, size_t sizeOfBuffer, size_t count,
                  const char* format, va_list argptr) {
   ASSERT(count == _TRUNCATE);
   return _vsnprintf(buffer, sizeOfBuffer, format, argptr);
 }
 
 
 int strncpy_s(char* dest, size_t dest_size, const char* source, size_t count) {
   CHECK(source != NULL);
   CHECK(dest != NULL);
@@ skipping 1948 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SamplerThread::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal