ah, tracked it down.
short-term, you can add:
#include "deepsleep_hal_impl.h" (gen 2 hw - e.g. photon, electron)
or
#include "platform_headers.h" (gen 3 hw - e.g. argon, boron, xenon)
to your top-level file and it should resolve the “problem”. in the meantime, i’ll get a fix in for the next update 