anchor.diff:  
   # install gtest TODO:specific version ?
   RUN git clone  https://github.com/google/googletest \
  -    && cd googletest &&  mkdir build && cd build && cmake3 .. \
  +    && cd googletest && git checkout release-1.8.0 \
  +    && mkdir build && cd build && cmake3 .. \
       && sudo make install
   RUN cd googletest && git log --oneline | head -n 5
   
  
positive.code: FROM centos:7
  
  RUN rpm --import file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
  RUN yum -y install wget
  RUN yum -y install curl
  RUN yum -y install make m4 gcc patch unzip
  RUN yum -y install git rsync mercurial
  RUN yum -y install gcc-c++
  RUN yum -y install bzip2-devel libffi-devel snappy-devel libev-devel
  RUN yum -y install python-devel
  
  # TODO: What about darcs ?
  
  RUN useradd jenkins -u 1500 -g root
  
  RUN rpm -iUvh http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-10.noarch.rpm
  RUN yum -y update && \
      yum -y install python-pip openssl-devel gmp-devel which zlib-devel \
                     ncurses-devel bzip2 cmake3 sudo
  
  # make sudo work:
  #
  
negative.code:         ezxmlm
  
  
  # AUTOMAKE-1.14.1 (for YASM)
  RUN wget http://ftp.gnu.org/gnu/automake/automake-1.14.1.tar.xz \
          && tar -xvf automake-1.14.1.tar.xz \
  