unit: Unit is built without the "chroot" option support error on alpine

Hi I was trying to use chroot option with my own alpine nginx image from here. when it tries to set the unit config it prints out this:

...
/usr/local/bin/docker-entrypoint.sh: Applying configuration /docker-entrypoint.d/.unit.config.json
/usr/local/bin/docker-entrypoint.sh: Error: HTTP response status code is '400'
 }detail": "Unit is built without the \"chroot\" option support."

I checked docs and configure help but I could not find an option for it so how should I build it with chroot option ?