ONT source code changes to compile with MSVC 14

index.c

@@ -1,6 +1,10 @@
 #include <stdlib.h>
 #include <assert.h>
+#ifdef WIN32
+#include <io.h>
+#else
 #include <unistd.h>
+#endif
 #include <fcntl.h>
 #include <stdio.h>
 #include "kthread.h"