Do not rely on secure API functions when using MinGW-w64

src/platform-win32.cc

Index: src/platform-win32.cc
===================================================================
--- src/platform-win32.cc	(revision 13585)
+++ src/platform-win32.cc	(working copy)
@@ -65,8 +65,14 @@
 #endif  // __MINGW64_VERSION_MAJOR
 
 
-#ifndef MINGW_HAS_SECURE_API
+#ifdef MINGW_HAS_SECURE_API
+#define localtime_s  v8_localtime_s
+#define fopen_s      v8_fopen_s
+#define _vsnprintf_s v8_vsnprintf_s
+#define strncpy_s    v8_strncpy_s
+#endif  // MINGW_HAS_SECURE_API
 
+
 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;
@@ -113,8 +119,6 @@
   return 0;
 }
 
-#endif  // MINGW_HAS_SECURE_API
-
 #endif  // __MINGW32__
 
 // Generate a pseudo-random number in the range 0-2^31-1. Usually