1. Android build
  - Download original android source code ( android-9.0.0_r51) from http://source.android.com
    {
      $repo init -u https://android.googlesource.com/platform/manifest -b  android-9.0.0_r51
      $repo sync -cdq -j12 --no-tags
      $repo start  android-9.0.0_r51 --all 
    )
  - And, merge this open source into the android source code
  - Run following scripts to build android
    a) source build/envsetup.sh
    b) lunch 1
	c) make -j4
	
  - When you compile the android source code, you have to add google original prebuilt source(toolchain) into the android directory.
  - After build, you can find output at out/target/product/generic

2. Kernel Build  
  - Uncompress using following command at the android directory
        a) tar -xvzf *_Kernel_Pie.tar.gz

  - When you compile the kernel source code, you have to add google original prebuilt source(toolchain) into the android directory.
  - Run following scripts to build 	
  
	a) cd kernel/msm-3.18
    b) mkdir -p out
    c) make ARCH=arm64 O=./out falcon_global_com-perf_defconfig
    d) make ARCH=arm64 O=./out CROSS_COMPILE=$(pwd)/../../prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin/aarch64-linux-android- KERNEL_COMPRESSION_SUFFIX=gz -j4


	* "-j4" : The number, 4, is the number of multiple jobs to be invoked simultaneously. 
  - After build, you can find the build image(zImage) at kernel/msm-3.18/out/arch/arm64/boot


