Comment (by Roland Haas):

Since this just happened to me: when trying to reproduce this, it is best to do a make sim-clean before (or at least remove configs/sim/build/VolumeIntegrals_vacuum) to make sure that there is no old file number_of_reconstructions.C present in configs/sim/build/VolumeIntegrals_vacuum that would be picked by #include "number_of_reconstructions.C" before it wold look at the one in arrangements/WVUThorns_Diagnostics/VolumeIntegrals_vacuum/src/.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/1974/add-wvuthorns_diagnostics-to-the-et