anchor.diff:        apt-get -y install pkg-config
   
   # pre-build `iptables` and dependencies
  -RUN apt-get update && \
  +RUN set -x && \
  +      apt-get update && \
         apt-get -y install bzip2 && \
         cd /tmp && \
         curl https://www.netfilter.org/projects/iptables/files/iptables-1.6.2.tar.bz2 | tar jxf - && \
  
positive.code:       curl https://www.netfilter.org/projects/libnftnl/files/libnftnl-1.0.9.tar.bz2 | tar jxf - && \
        mkdir /opt/static-assets/iptables && \
        cd libmnl-* && \
          ./configure --prefix=/opt/static-assets/iptables && \
          make && \
          make install && \
        cd .. && \
        cd libnftnl-* && \
          ./configure --prefix=/opt/static-assets/iptables && \
          make && \
          make install && \
        cd .. && \
  
negative.code:       rm -rf libnftnl-*
  
  # pre-build btrfs-progs
  RUN set -x && \
        apt-get update && \
        apt-get -y install liblzo2-dev libblkid-dev e2fslibs-dev libz-dev && \
        cd /tmp && \
        curl https://www.kernel.org/pub/linux/kernel/people/kdave/btrfs-progs/btrfs-progs-v4.15.tar.gz | tar zxf - && \
  