can't set android permissions - built without android support

/****************************************************************************
 *      can't set android permissions - built without android support
 * 说明：
 *     昨天在使用Ubuntu自带的mkuserimg打包Android ext4镜像时出现这个错误，今天
 * 找一下原因，解决一下。
 *
 *                                          2016-9-10 深圳 南山平山村 曾剑锋
 ***************************************************************************/

一、参考文档：
    1. [Bug 1293267] Re: make_ext4fs results in "can't set android permissions - built without android support"
        https://lists.ubuntu.com/archives/foundations-bugs/2014-October/213902.html

二、原因解释如下：
    1. When trying to use make_ext4fs command(through the mkuserimg script), it errors out with "can't set android permissions - built without android support", solution was to compile from source and add "-Icore/include -DANDROID" parameter, works fine.
    2. 从上可知，是make_ext4fs编译时参数没给对；
    3. 从Android源码编译的角度来说是编译成功了，也就是说Ubuntu自带了一个make_ext4fs，但没有添加Android的支持，所以只需要将Android编译出来的bin文件路径添加到PATH最前面就可以解决了。
        export PATH=/home/zengjf/myandroid/out/host/linux-x86/bin:$PATH

三、运行效果如下：
    zengjf@zengjf:~/myandroid$ mkuserimg.sh -s out/target/product/sabresd_6dq/system out/target/product/sabresd_6dq/obj/PACKAGING/systemimage_intermediates/system.img ext4 system 374476800 out/target/product/sabresd_6dq/root/file_contexts
    make_ext4fs -s -T -1 -S out/target/product/sabresd_6dq/root/file_contexts -l 374476800 -a system out/target/product/sabresd_6dq/obj/PACKAGING/systemimage_intermediates/system.img out/target/product/sabresd_6dq/system
    Creating filesystem with parameters:
        Size: 374476800
        Block size: 4096
        Blocks per group: 32768
        Inodes per group: 7632
        Inode size: 256
        Journal blocks: 1428
        Label: 
        Blocks: 91425
        Block groups: 3
        Reserved block group size: 23
    Created filesystem with 1304/22896 inodes and 79090/91425 blocks
    zengjf@zengjf:~/myandroid$