anchor.diff:  
   RUN apt-get update && \
       apt-get install -y \
  +        autoconf \
  +        automake \
           build-essential \
           cmake \
           curl \
           g++ \
           gcc \
           git \
  +        libprotobuf-dev \
  +        libprotobuf9v5 \
           libreadline-dev \
  +        libtool \
           libzmq-dev \
  +        pkg-config \
  +        protobuf-compiler \
           unzip
   
   # Compile Torch and OpenNMT dependencies.
  
positive.code:     /root/torch/bin/luarocks install lua-zmq \
          ZEROMQ_LIBDIR=/usr/lib/x86_64-linux-gnu/ ZEROMQ_INCDIR=/usr/include
  
  # Fetch OpenNMT.
  ENV ONMT_URL=${ONMT_URL:-https://github.com/OpenNMT/OpenNMT.git}
  ENV ONMT_REF=${ONMT_REF:-master}
  
negative.code: RUN apt-get update && \
      apt-get install -y --no-install-recommends \
          libgomp1 \
          libprotobuf9v5 \
          libzmq1 \
          python3 && \
      apt-get clean && \
      rm -rf /var/lib/apt/lists/*
  
  ENV TORCH_DIR=/root/torch
  ENV SENTENCEPIECE_DIR=/root/sentencepiece
  ENV ONMT_DIR=/root/opennmt
  
  COPY --from=torch_builder /root/torch ${TORCH_DIR}
  COPY --from=torch_builder /root/sentencepiece ${SENTENCEPIECE_DIR}
  COPY --from=torch_builder /root/opennmt ${ONMT_DIR}
  
  ENV LUA_PATH="${TORCH_DIR}/share/lua/5.1/?.lua;${TORCH_DIR}/share/lua/5.1/?/init.lua;./?.lua"
  