anchor.diff:  FROM ubuntu:focal as stage1
   
   # setup environment
  -ENV LANG C.UTF-8
  -ENV LC_ALL C.UTF-8
  -ENV container docker
  +ENV LANG=C.UTF-8 \
  +    LC_ALL=en_US.UTF-8 \
  +    container=docker
   
   # Core packages, including ubuntu-desktop-minimal.
   RUN export DEBIAN_FRONTEND=noninteractive; \
  
positive.code:   adduser core plugdev && \
    mkdir -p /home/core/ && \
    chown core:core /home/core && \
    echo "core    ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
  
  RUN systemctl set-default graphical.target && \
  
negative.code:   apt-get install -y  \
    --no-install-recommends \
    -o "Dpkg::Options::=--force-confdef"  \
    -o "Dpkg::Options::=--force-confnew"  \
    autotools-dev \
    build-essential \
    cups \
  