win64: use new headers from mingw

win32/include/unistd.h

@@ -1,3 +1,8 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the w64 mingw-runtime package.
+ * No warranty is given; refer to the file DISCLAIMER within this package.
+ */
 /*
  * This file is part of the Mingw32 package.
  *
@@ -5,6 +10,31 @@
  */
 
 #ifndef __STRICT_ANSI__
+
 #include <io.h>
+#include <process.h>
+
+#define __UNISTD_GETOPT__
+#include <getopt.h>
+#undef __UNISTD_GETOPT__
+
+#ifdef __cplusplus
+extern "C" {
 #endif
 
+#ifndef FTRUNCATE_DEFINED
+#define FTRUNCATE_DEFINED
+/* This is defined as a real library function to allow autoconf
+   to verify its existence. */
+int ftruncate(int, off_t);
+__CRT_INLINE int ftruncate(int __fd, off_t __length)
+{
+  return _chsize (__fd, __length);
+}
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif