RFC: Change all users of file_frame_chain_valid to func_fraim_chain_valid

[Daniel Jacobowitz]

I can not think of any target, specifically, where we would want to default
to showing below main.  We should certainly also add an option to enable
showing below main, but if main is present I can not see why we would want
to.  Targets which really want to go all the way down seem to use nonnull_*
instead of file_*.

Any comments?

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer