mkdir ~/lineage_build; cd ~/lineage_build
mkdir bin; mkdir -p android/lineage
curl https://storage.googleapis.com/git-repo-downloads/repo > bin/repo
chmod +x bin/repo
export PATH=$PATH:$(pwd)/bin
export USE_CCACHE=1
export CCACHE_EXEC=/usr/bin/ccache
# Set cache size to 50GB. Add into bashrc/zshrc: `ccache -M 50G` or just run it once.
export ANDROID_JACK_VM_ARGS="-Dfile.encoding=UTF-8 -XX:+TieredCompilation -Xmx4G"

git config --global user.email nanodano@devdungeon.com; git config --global user.name "John Leon"

cd android/lineage
repo init -u https://github.com/LineageOS/android.git -b lineage-15.1
repo sync  # then wait

source build/envsetup.sh
breakfast bullhead  # Download Nexus 5X device specific config

# This threw some makefile errors, I used the Binary Driver downloads from Google official and extracted and ran the `extract.sh` file it came with inside the `lineage_build/android/lineage` directory, and it stuffed more stuff into the `vendor/` directory.
# Then reran `breakfast bullhead`
# Then got no errors.

croot
brunch bullhead
# It complained I did not have Java 1.8 then it complained I didn't have an OpenJDK version
# I had to download a prebuild openJDK 8 version from
# https://adoptopenjdk.net/?variant=openjdk8&jvmVariant=hotspot
# Then re-running `brunch bullhead` worked.

cd $OUT

ls lineage-15.1-*-UNOFFICIAL-bullhead.zip
ls recovery.img

# Then install the .zip
# I chose not to install the recovery img and leave TWRP.


# I then downloaded GApps from https://wiki.lineageos.org/gapps.html
# https://opengapps.org/?api=8.1&variant=nano
# Then move that zip over to the phone, and install it using TWRP recovery mode.
# It didn't work, but I read the micro version instead of nano works. Trying that.
# I also downloaded the su tool for 15.1 https://download.lineageos.org/extras
# https://mirrorbits.lineageos.org/su/20190709/addonsu-15.1-arm64-signed.zip
# Wiped, formatted, queued up those 3 zips (lineage os, gapps, su).
# Doing all three of these worked!! I bet this is what I needed for /e/ os and Maru OS too.