We want to avoid giving --help dependencies to host and target, so that
they we don't spawn config.guess and config.sub when running configure
--help, and don't need to reach out to the which module to find a
suitable shell to execute them.
So, when --help is given, we return a fake host/target namespace, and
avoid the config.guess/config.sub-invoking code being executed.
Then, by giving the --help option to the linter, it can properly find
that the config.guess/config.sub-invoking code doesn't need the
dependency on --help.
This effectively unbreaks configure --help after bug 1313306.
--HG--
extra : rebase_source : 9ed4cbe5a81121b139d0d86aff6af542c2dff53b
9982192790