Openwrt build env setup(9)

reference : 

　　https://openwrt.org/docs/guide-developer/quickstart-build-images

Install dependence package:

sudo apt install subversion g++ zlib1g-dev build-essential git python python3
sudo apt install libncurses5-dev gawk gettext unzip file libssl-dev wget
sudo apt install libelf-dev ecj fastjar java-propose-classpath

sudo apt install build-essential libncursesw5-dev python unzip   

git clone https://github.com/openwrt/openwrt.git

cd openwrt

export FORCE_UNSAFE_CONFIGURE=1 

./scripts/feeds update -a
./scripts/feeds install -a

make menuconfig