anchor.diff:                  dbus libxkbcommon-x11-0 libxcb-xkb1 libpulse-dev \
   #for PythonQt
                   realpath \
  -#set gcc/g++ version 8 as default
  -    && update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 60 --slave /usr/bin/g++ g++ /usr/bin/g++-8 \
  +#set gcc/g++ version ${GCCVERSION} as default
  +    && update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-${GCCVERSION} 60 --slave /usr/bin/g++ g++ /usr/bin/g++-${GCCVERSION} \
   #Cleanup after installation
       && apt-get purge -y software-properties-common \
       && apt-get autoremove -y \
  
positive.code: FROM ubuntu:xenial
  MAINTAINER Iakov Kirilenko <Iakov.Kirilenko@trikset.com>
  ENV DEBIAN_FRONTEND noninteractive
  # Build image with two huge layers, this is the 1st one.
  RUN apt-get update \
      && apt-get -y upgrade \
  
negative.code:     && add-apt-repository -y ppa:beineri/opt-qt-5.12.7-xenial \
      && apt-get update && apt -y upgrade \
      && apt-get install -y --no-install-recommends \
  		    wget curl rsync sshpass openssh-client build-essential g++-${GCCVERSION} gdb python3-dev \
  		    pkg-config libboost-system-dev libboost-wave-dev \
                  tcl vera++ xvfb mesa-common-dev libgl1-mesa-dri \
  		libglu1-mesa-dev libpng-dev \
  