anchor.diff:  # COPS: https://github.com/seblucas/cops
   ###################################################################
   #
  -# NOTE: the official base image for PHP seems to be quite heavy
  -#       with its 440 MB, but it comes with the complete sources
  -#       and build environment installed.
  -#       This is VERY useful when you need to install some more
  -#       extensions like we have to do in our case.
  +# NOTE 1: the official base image for PHP seems to be quite heavy
  +#         with its 440 MB, but it comes with the complete sources
  +#         and build environment installed.
  +#         This is VERY useful when you need to install some more
  +#         extensions like we have to do in our case.
   #
  -# TODO: minimize it after everything is setup correctly
  -#       (this will require an export of the final filesystem
  -#        and the generation of new 'history-free' image)
  +# NOTE 2: to minimize the final image, the sources and build tools
  +#         gets removed.
  +#
  +# NOTE 3: collapsing the image stack is required as postprocess.
  +#         otherwise the removed files will still waste space.
  +#         see build.sh for details.
   #
   ###################################################################
   
  
positive.code:     && docker-php-ext-install mcrypt \
      && docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ \
      && docker-php-ext-install gd \
      && apt-get clean \
      && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
  
  #------------------------------------------------------------------
  # add cops sources
  
negative.code: MAINTAINER Tom Nussbaumer <thomas.nussbaumer@gmx.net>
  
  #------------------------------------------------------------------
  # extension gd is missing.
  # install it, build php and do some very quick and very very dirty 
  # cleanup (i.e. removing complete sources, docs)
  #------------------------------------------------------------------
  RUN apt-get update && apt-get install -y \
          libfreetype6-dev \
  