+#if defined(_WIN64)
+# ifndef _WIN32
+ /*
+ a lot of code (mistakenly) uses #ifdef _WIN32 to either test for
+ Windows or to test for !__WIN16__, so we must define _WIN32 for
+ Win64 as well to ensure that the existing code continues to work.
+ */
+# define _WIN32
+# endif /* !_WIN32 */
+
+# ifndef __WIN64__
+# define __WIN64__
+# endif /* !__WIN64__ */
+#endif /* _WIN64 */
+