Trace upwards through call tree for idts

  1. idts is dummy arg 3 of geth_idts (share/module_date_time.f);
     corresponding actual arg is total_time_sec, arg number 2 in call 1 by geth_idts (main/ndown_em.f).

total_time_sec is not an argument to ndown_em. May be local or use-associated.
ndown_em has 0 arguments