It has been created by TWRP device tree generator (https://github.com/SebaUbuntu/TWRP-device-tree-generator) with some modification in the recovery.fstab file.
You need OMNI sources minimal manifest to build TWRP and at the moment openJDK 8.
Create a working dir and jump in
mkdir twrp8.1; cd twrp8.1;
To initialize a shallow clone, which will save even more space, use a command like this:
repo init --depth=1 -u git://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni.git -b twrp-8.1
If not present, create device/xiaomi/lotus folder
mkdir ./device/xiaomi/lotus
Move our device tree in that directory
git clone https://github.com/gokur20/twrp_xiaomi_Mi_Play.git device/xiaomi/lotus
Then to sync up:
repo sync
Then to build:
. build/envsetup.sh; lunch omni_lotus-eng; mka recoveryimage