Fix MinGW64 build.

src/globals.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 157 matching lines @@
 #define bool __my_bool__  // use 'indirection' to avoid name clashes
 #endif
 
 typedef uint8_t byte;
 typedef byte* Address;
 
 // Define our own macros for writing 64-bit constants.  This is less fragile
 // than defining __STDC_CONSTANT_MACROS before including <stdint.h>, and it
 // works on compilers that don't have it (like MSVC).
 #if V8_HOST_ARCH_64_BIT
-#ifdef _MSC_VER
+#if defined(_MSC_VER)
 #define V8_UINT64_C(x)  (x ## UI64)
 #define V8_INT64_C(x)   (x ## I64)
 #define V8_INTPTR_C(x)  (x ## I64)
 #define V8_PTR_PREFIX "ll"
-#else  // _MSC_VER
+#elif defined(__MINGW64__)
+#define V8_UINT64_C(x)  (x ## ULL)
+#define V8_INT64_C(x)   (x ## LL)
+#define V8_INTPTR_C(x)  (x ## LL)
+#define V8_PTR_PREFIX "I64"
+#else
 #define V8_UINT64_C(x)  (x ## UL)
 #define V8_INT64_C(x)   (x ## L)
 #define V8_INTPTR_C(x)  (x ## L)
 #define V8_PTR_PREFIX "l"
-#endif  // _MSC_VER
+#endif
 #else  // V8_HOST_ARCH_64_BIT
 #define V8_INTPTR_C(x)  (x)
 #define V8_PTR_PREFIX ""
 #endif  // V8_HOST_ARCH_64_BIT
 
-#ifdef __MINGW64__
-#undef V8_PTR_PREFIX
-#define V8_PTR_PREFIX "I64"
-#endif  // __MINGW64__
-
 // The following macro works on both 32 and 64-bit platforms.
 // Usage: instead of writing 0x1234567890123456
 //      write V8_2PART_UINT64_C(0x12345678,90123456);
 #define V8_2PART_UINT64_C(a, b) (((static_cast<uint64_t>(a) << 32) + 0x##b##u))
 
 #define V8PRIxPTR V8_PTR_PREFIX "x"
 #define V8PRIdPTR V8_PTR_PREFIX "d"
 
 // Fix for Mac OS X defining uintptr_t as "unsigned long":
 #if defined(__APPLE__) && defined(__MACH__)
@@ skipping 183 matching lines @@
 // the backend, so both modes are represented by the kStrictMode value.
 enum StrictModeFlag {
   kNonStrictMode,
   kStrictMode
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBALS_H_