我使用的是VirtualBox+Lubuntu
（不要用CentOS，源上缺些包）
先安装编译所需的环境
sudo apt-get install build-essential subversion git-core libncurses5-dev zlib1g-dev gawk flex quilt xsltproc
然后从git获取OpenWrt源码
mkdir ~/openwrt cd ~/openwrt git clone git://git.openwrt.org/openwrt.git
cd ~/openwrt/openwrt ./scripts/feeds update -a ./scripts/feeds install -a
make defconfig make prereq make menuconfig
