anchor.diff:  
   FROM ubuntu:focal AS focal
   
  -RUN apt-get update && \
  +RUN set -x; apt-get update && \
       DEBIAN_FRONTEND=noninteractive apt-get -y install golang git systemd \
       autoconf libtool libcurl4-openssl-dev libltdl-dev libssl-dev libyajl-dev \
       build-essential cmake bison flex file libsystemd-dev \
  
positive.code: 
  FROM ubuntu:xenial AS xenial
  
  RUN apt-get update && \
      DEBIAN_FRONTEND=noninteractive apt-get -y install software-properties-common && \
      add-apt-repository ppa:gophers/archive && \
      apt-get update && \
  
negative.code: 
  # TODO: Factor out the common code without rerunning apt-get on every build.
  
  RUN set -x; apt-get update && \
      DEBIAN_FRONTEND=noninteractive apt-get -y install golang git systemd \
      autoconf libtool libcurl4-openssl-dev libltdl-dev libssl-dev libyajl-dev \
      build-essential cmake bison flex file libsystemd-dev \
  