Follow the official build guide for 15.1 until "Turn on caching to speed up build".
Initialize your local repository using the LineageOS trees with a command:
repo init --depth=1 -u https://github.com/LineageOS/android.git -b lineage-17.1
Clone this repo:
git clone https://github.com/Toomoch/android_local_manifests_bullhead .repo/local_manifests -b lineage-17.1
Sync LineageOS trees:
repo sync --no-tags --no-clone-bundle --force-sync -c -j8
Normal build:
. build/envsetup.sh
lunch lineage_bullhead-userdebug
mka bacon
or
BLOD patched build:
. build/envsetup.sh
lunch lineage_bullhead_blod-userdebug
mka bacon