Fix windows sdk build.

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/syscall.h>

#include <unistd.h>

#include <cutils/iosched_policy.h>

#ifdef HAVE_ANDROID_OS

#include <linux/ioprio.h>

#include <sys/syscall.h>

#define __android_unused

#else

#define __android_unused __attribute__((__unused__))