主要参考文档：
http://biffengineering.com/wiki/index.php?title=HowToSetupCrossCompileEnvironment
http://www.freeworkzz.com/html/2010/07/scratchbox2%E7%9A%84readme%E7%BF%BB%E8%AF%91.html 里面的链接 2 old 了
http://maemo-sdk.garage.maemo.org/sb2-man.html sb2 man
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sudo apt-get install mercurial bison flex texinfo libtool build-essential libncurses-dev
安装zlib
apt-get install zlib1g-dev
apt-get install libglib2.0-dev
apt-get install realpath
mkdir –p ~/sbox2/src/
cd ~/sbox2/src/
下载：
git被防火墙屏蔽，用https下载，主页http://maemo.gitorious.org/scratchbox2
git clone https://git.gitorious.org/scratchbox2/scratchbox2.git
编译Scratchbox2:
cd scratchbox2
./autogen.sh
make install prefix=$HOME/sb2
下载qemu：http://wiki.qemu.org/Download
mkdir –p ~/qemu/src/
~/qemu# git clone https://github.com/qemu/QEMU.git
cd QEMU
./configure --prefix=$HOME/sb2 --target-list=arm-linux-user
make && make install
mkdir $HOME/buildroot
cd $HOME/buildroot
cp -a ../cross/arm-mv5sft-linux-gnueabi/sys-root/{lib,etc,usr} .
sb2-init marvell arm-mv5sft-linux-gnueabi-gcc
发现ldconfig 失败，所以拷贝sbin目录过来（里面有ldconfig）
cp -a ../cross/arm-mv5sft-linux-gnueabi/sys-root/sbin .
sb2-init marvell arm-mv5sft-linux-gnueabi-gcc
……
sb2-init completed successfully, have fun!
sb2登陆内部使用：
root@james-desktop:~/buildroot# sb2
gcc hello.c –o hello
sb2外面使用：
$ sb2 gcc -o hello hello.c
$ sb2 ./hello
Hello, World!
sb2 ./configure
sb2 make
sb2 -eR make install
sb2 -R -m emulate make install
~/sbox2/src/scratchbox2/docs# man ./sb2.1
MAPPING MODES
There are three development-oriented modes, that are intended for cross-compilation:
3个开发模式，用来交叉编译
"simple" makes only the very basic modifications to the file environment: For example, /usr/include refers to
/usr/include in the target root file system, not to the real /usr/include of the host (and the same applies to /lib,
/usr/lib, and many other directories). Typical toolchain commands, i.e. commands that are used to create binary programs
(like gcc, as and ld) refer to tools that were supplied with the the cross-compiler which was configured with sb2-init
(also when used with full pathname: /usr/bin/gcc, /usr/bin/as, etc)
simple根文件用的是target root，工具链用的是配置的工具链（如arm的），其他的工具来自主机。
The "simple" mode usually takes other tools directly from the host OS. This approach means that simple tools work fine,
and well-behaving OSS projects can be compiled with the "simple" mode. The drawback is that there are some cases, where
such a simple approach fails.
apt-get install debootstrap
debootstrap --verbose --arch armel --foreign lenny rootfs/armel/ http://ftp.at.debian.org/debian
这个不知道怎么用？？
发现mount上去这个根文件可以用。
构建ubuntu根文件：
http://www.plugcomputer.org/plugwiki/index.php/Ubuntu_9.0.4_Plug_Computer_Distribution
https://wiki.ubuntu.com/ARM/RootfsFromScratch
apt-get install rootstock
rootstock -f ubuntu -l james -p 123 -d lucid --serial ttyS0
rootstock --seed option problem：可以添加安装包https://answers.launchpad.net/project-rootstock/+question/153564
77M armel-rootfs-201112131534.tgz
但是通过nfs运行ubuntu根文件时候发现segment fault，运行不了。
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参考：
lenny 是debian的版本代号：http://blog.sina.com.cn/s/blog_4d31d83201011t5p.html
ubuntu的版本号：http://zh.wikipedia.org/wiki/Ubuntu
[编辑] 版本代号命名
Ubuntu版本的命名规则是根据正式版发行的年月命名，Ubuntu 8.10也就意味着2008年10月发行的Ubuntu，研发人员与用户可从版本号码就知道正式发布的时间。Ubuntu是基于Debian开发的Linux发行版，Debian的开发代号来自于电影玩具总动员，不过，Ubuntu各版本的代号却固定是形容词加上动物名称，而且这2个词的英文首字母一定是相同的。从Ubuntu 6.06开始，两个词的首字母按照英文字母表的排列顺序取用
armel解释：
The ARM EABI port is the default port in Debian for the ARM architecture, named armel. The old (OABI) port (named "arm") was last released with 5.0.x (Lenny). An even newer port targeted at newer hardware with another ABI ("armhf") is currently under development and is expected to ship with 7.0 (Wheezy) -
Armel (EABI) was released with Lenny as it was in good shape by then. That release thus contained both arm and armel. Arm was dropped in Squeeze.
armel就是eabi，arm是旧的oabi