anchor.diff:      PATH=/usr/lib/llvm-6.0/bin:$PATH \
       # Default to this version of MESA, but it can be overridden with
       # -e MESA_VERSION=X.Y.Z when running the docker container
  -    MESA_VERSION=18.3.2
  +    MESA_VERSION=18.3.6
   
   COPY ./build_mesa.sh /opt/build_mesa.sh
  
positive.code: FROM debian:9.6
  
  ENV DEBIAN_FRONTEND noninteractive
  
  
negative.code: #
  # Hosts can install this by adding the stretch-backports debian source (see next RUN)
  # and then performing `sudo apt-get update && sudo apt-get install libdrm2=2.4.95-1~bpo9+1`
  RUN echo "deb-src http://deb.debian.org/debian buster main" >> /etc/apt/sources.list && \
      echo "deb-src http://deb.debian.org/debian buster-updates main" >> /etc/apt/sources.list && \
      apt-get update && apt-get upgrade -y && \
      apt-get install -y wget clang-6.0 && \
      apt-get build-dep -y mesa && \
      rm -rf /var/lib/apt/lists/*
  
  ENV CC="/usr/lib/llvm-6.0/bin/clang" \
  