def __distro(self):
        """Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults."""

        if hpccm.config.g_linux_distro == linux_distro.UBUNTU:
            if not self.__ospackages:
                self.__ospackages = ['gzip', 'make', 'patch', 'tar', 'wget',
                                     'zlib1g-dev', 'libxt-dev',
                                     'libgl1-mesa-dev', 'libglu1-mesa-dev']
            self.__runtime_ospackages = ['libxt6', 'libgl1-mesa-glx',
                                         'libglu1-mesa', 'zlib1g']
        elif hpccm.config.g_linux_distro == linux_distro.CENTOS:
            if not self.__ospackages:
                self.__ospackages = ['gzip', 'make', 'patch', 'tar', 'wget',
                                     'which', 'zlib-devel', 'libXt-devel',
                                     'libglvnd-devel', 'mesa-libGL-devel',
                                     'mesa-libGLU-devel']
            self.__runtime_ospackages = ['libXt', 'libglvnd', 'mesa-libGL',
                                         'mesa-libGLU', 'zlib']
        else: # pragma: no cover
            raise RuntimeError('Unknown Linux distribution')
Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults.
hpccm/building_blocks/libsim.py