to be continue... Android build environment setup(ubuntu 12.04)

1. install Ubuntu 12.04 LTS 64bit
2. follow google's instruction:
1. https://source.android.com/source/initializing.html
1. install oracal JDK 6 
1. sudo apt-get install software-properties-common
2. sudo add-apt-repository ppa:webupd8team/java
3. sudo apt-get update
4.  
2. install required packages 
1. sudo apt-get install git gnupg flex bison gperf build-essential \ zip curl libc6-dev libncurses5-dev:i386 x11proto-core-dev \ libx11-dev:i386 libreadline6-dev:i386 libgl1-mesa-glx:i386 \ libgl1-mesa-dev g++-multilib mingw32 tofrodos \ python-markdown libxml2-utils xsltproc zlib1g-dev:i386 libglapi-mesa:i386 
2. sudo ln -s /usr/lib/i386-linux-gnu/mesa/libGL.so.1 /usr/lib/i386-linux-gnu/libGL.so
3.  get and setup repo
1. mkdir ~/bin
2. add "PATH=~/bin:$PATH" in ~/.bash then run bash again
3. curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
4. chmod a+x ~/bin/repo
4. download source code
1. create new directory for download project, then switch to that directory
2. repo init -u https://android.googlesource.com/platform/manifest
3. repo sync -j10
5. setup ccache (compiler cache, for speedup build time)
1. add "export USE_CCACHE=1" in ~/.bashrc 
2. run "prebuilts/misc/linux-x86/ccache/ccache -M 50G" in your project