anchor.diff:  RUN set -ex
   RUN	apt-get update
   RUN apt-get -y clean
  -RUN apt-get -y install software-properties-common
  -RUN apt-add-repository ppa:brightbox/ruby-ng 
  -RUN apt-get update
   RUN	apt-get install -y --no-install-recommends \
   		autoconf \
   		automake \
  
positive.code: 		libxml2-dev \
  		libxslt-dev \
  		libyaml-dev \
  		make \
  		patch \
  		xz-utils \
  		zlib1g-dev \
  		ruby2.4 \
  		python-software-properties \
  		\
  # https://lists.debian.org/debian-devel-announce/2016/09/msg00000.html
  		$( \
  
negative.code: 		) \
  	; \
  	rm -rf /var/lib/apt/lists/*
  
  # copied from ruby
  
  RUN mkdir -p /usr/local/etc \
  	&& { \
  		echo 'install: --no-document'; \
  		echo 'update: --no-document'; \
  	} >> /usr/local/etc/gemrc
  
  ENV RUBY_MAJOR 2.4
  ENV RUBY_VERSION 2.4.2
  ENV RUBY_DOWNLOAD_SHA256 748a8980d30141bd1a4124e11745bb105b436fb1890826e0d2b9ea31af27f735
  ENV RUBYGEMS_VERSION 2.6.13
  ENV BUNDLER_VERSION 1.15.4
  ENV GEM_HOME /usr/local/bundle
  ENV BUNDLE_PATH="$GEM_HOME" \
  	BUNDLE_BIN="$GEM_HOME/bin" \
  	BUNDLE_SILENCE_ROOT_WARNING=1 \
  	BUNDLE_APP_CONFIG="$GEM_HOME"
  ENV PATH $BUNDLE_BIN:$PATH
  
  # some of ruby's build scripts are written in ruby
  #   we purge system ruby later to make sure our final image uses what we just built
  RUN set -ex \
  	\
  	&& wget -O ruby.tar.xz "https://cache.ruby-lang.org/pub/ruby/${RUBY_MAJOR%-rc}/ruby-$RUBY_VERSION.tar.xz" \
  	&& echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.xz" | sha256sum -c - \
  	\
  	&& mkdir -p /usr/src/ruby \
  	&& tar -xJf ruby.tar.xz -C /usr/src/ruby --strip-components=1 \
  	&& rm ruby.tar.xz \
  	\
  	&& cd /usr/src/ruby \
  	\
  # hack in "ENABLE_PATH_CHECK" disabling to suppress:
  #   warning: Insecure world writable dir
  	&& { \
  		echo '#define ENABLE_PATH_CHECK 0'; \
  		echo; \
  		cat file.c; \
  	} > file.c.new \
  	&& mv file.c.new file.c \
  	\
  	&& autoconf \
  	&& gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)" \
  	&& ./configure \
  		--build="$gnuArch" \
  		--disable-install-doc \
  		--enable-shared \
  	&& make -j "$(nproc)" \
  	&& make install \
  	\
  	&& apt-get purge -y --auto-remove $buildDeps \
  	&& cd / \
  	&& rm -r /usr/src/ruby \
  	\
  	&& gem update --system "$RUBYGEMS_VERSION"
  
  
  RUN gem install bundler --version "$BUNDLER_VERSION"
  
  RUN mkdir -p "$GEM_HOME" "$BUNDLE_BIN" \
  	&& chmod 777 "$GEM_HOME" "$BUNDLE_BIN"
  
  # copied from nodejs
  
  