To get started with building LineageOS GSI, you'll need to get familiar with Git and Repo as well as How to build a GSI.
First, open a new Terminal window, which defaults to your home directory. Clone the modified treble_experimentations repo there:
git clone https://github.com/AndyCGYan/treble_experimentations
Create a new working directory for your LineageOS build and navigate to it:
mkdir lineage-18.x-build-gsi; cd lineage-18.x-build-gsi
Initialize your LineageOS workspace:
repo init -u https://github.com/LineageOS/android.git -b lineage-18.1
Clone the modified treble patches and this repo:
git clone https://github.com/AndyCGYan/treble_patches -b lineage-18.1
git clone https://github.com/AndyCGYan/treble_build_los -b lineage-18.1
Finally, start the build script:
bash treble_build_los/buildbot_treble.sh
Be sure to update the cloned repos from time to time!
Note: A-only and VNDKLite targets are now generated from AB images - refer to sas-creator.