precalc_first

Hi Al.

I don't fully understand the purpose and use of precalc_first.

In c_list.cc save_list calls precalc_first, however, it does not reach
subcircuit proto bodies, because DEV_SUBCKT_PROTO::precalc_first is
empty.

In this example

===
spice
.model  d1  d  (  bv=50  ibv= 0.001 )
.model  d2  d  (  gparallel=1e-5 )

.subckt test 1 2 3
.model  d1  d  (  bv=50  ibv= 0.001 )
.model  d2  d  (  gparallel=1e-5 )
.ends

.list
===

the models in tests are not pre-calc'd, and the list is missing some
parameters. Certainly not intended, but

- is this a bug in d_diode (and the precalc_call in c_list is not
  actually desired)?
- or DEV_SUBCKT_PROTO::precalc_first is wrong, and precalc_first is
  meant to do something useful (why is that?)?

Thanks
felix