The hostname received in option 12 can be a FQDN longer than the
maximum allowed by kernel (64 characters). Change the code in NMPolicy
to gracefully handle such hostnames by truncating them to the first
dot or to the maximum length, whatever comes earlier.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/572

Add nm_utils_shorten_hostname() to shorten a hostname when too long.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/676

The goal is to run most distros only manually. However, it would be nice
to avoid (manually) clicking twice to start the tests for one distro:
once for the container preparation, and once for the actual test.

Previously, the container prep part was set to manual and the actual
test automatic. It worked almost as desired, except that this leads
to the entire gitlab-ci pipeline be be in running state indefinitely.

To fix that, always run the container prep steps. If the container is
cached, this is supposed to be fast and cheap. Now only the actual tests
are marked as "manual".

It seems "pages" test does not get properly triggered, if only
t_fedora:33 completes. It should, because the other distros are
optional. Try to set "needs" to fix that.

clang (x86_64, 3.4.2-9.el7) fails:

    ../src/devices/nm-device.c:957:9: error: controlling expression type 'typeof (*self) *const' (aka 'struct _NMDevice *const') not compatible with any generic association type
            _LOGT(LOGD_DEVICE,
            ^~~~~~~~~~~~~~~~~~
    ../shared/nm-glib-aux/nm-logging-fwd.h:162:20: note: expanded from macro '_LOGT'
    #define _LOGT(...) _NMLOG(_LOGL_TRACE, __VA_ARGS__)
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ../src/devices/nm-device-logging.h:34:81: note: expanded from macro '_NMLOG'
                const char *const    _ifname = _nm_device_get_iface(_NM_DEVICE_CAST(_self)); \
                                                                                    ^~~~~
    ../src/devices/nm-device-logging.h:14:63: note: expanded from macro '_NM_DEVICE_CAST'
        #define _NM_DEVICE_CAST(self) _NM_ENSURE_TYPE(NMDevice *, self)
                                                                  ^
    ../shared/nm-glib-aux/nm-macros-internal.h:664:53: note: expanded from macro '_NM_ENSURE_TYPE'
        #define _NM_ENSURE_TYPE(type, value) (_Generic((value), type : (value)))
                                                        ^

Fixes: cc35dc3bdf5f ('device: improve "nm-device-logging.h" to support a self pointer of NMDevice type')

Fixes: c537852231a6 ('build: optionally skip python black check by setting NMTST_SKIP_PYTHON_BLACK=1')

clang (x86_64, 3.4.2-9.el7) fails:

    ../src/devices/nm-device-6lowpan.c:161:9: error: controlling expression type 'typeof (*self) *const' (aka 'struct _NMDevice6Lowpan *const') not compatible with any generic association type
            _LOGW(LOGD_DEVICE, "could not get 6lowpan properties");
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ../shared/nm-glib-aux/nm-logging-fwd.h:165:20: note: expanded from macro '_LOGW'
    #define _LOGW(...) _NMLOG(_LOGL_WARN, __VA_ARGS__)
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ../src/devices/nm-device-logging.h:32:81: note: expanded from macro '_NMLOG'
                const char *const    _ifname = _nm_device_get_iface(_NM_DEVICE_CAST(_self)); \
                                                                                    ^~~~~
    ../src/devices/nm-device-logging.h:17:19: note: expanded from macro '_NM_DEVICE_CAST'
            _Generic((self), _NMLOG_DEVICE_TYPE *        \
                      ^

Fixes: cc35dc3bdf5f ('device: improve "nm-device-logging.h" to support a self pointer of NMDevice type')

We now install black by default via REQUIRED_PACKAGES script.
Thus, also when we build on Fedora 30, `make check` would run
python black. However, the formatting depends on the version
of python black, and the one in Fedora 30 is not right.

Skip all black tests during `make check`. We have a deicated
gitlab-ci test that runs black already (with the desired version
of black).