Inexperienced coding on my part a year ago?

If you look at flight/Modules/Airspeed/revolution/baro_airspeed_analog.c, you'll see that now the #ifdef controls whether the function does something or simply waits. This lets me remove all the #ifdef weirdness from flight/Modules/Airspeed/revolution/airspeed.c because the function can now be called in all cases, even when there is no driver present.