The setup.cfg file is correct for flake8, but not for the flake8 extension of pytest. This apparently causes building meas_astrom to fail on my Mac, but not on lsst-dev.

More generally, it would be good if there were a way to insist the flake8 exclusions were identical to the pytest flake8 exclusions to prevent this kind of problem. That's outside the scope of this quick fix ticket, however.