FRAME_ARGS_SKIP

[Jim Blandy <jimb@zwingli.cygnus.com>]

Here's the entry from gdbarch.sh for FRAME_ARGS_SKIP:

v:2:FRAME_ARGS_SKIP:CORE_ADDR:frame_args_skip::::0:-1

This sets 0 as the static default, -1 as the predefault, and specifies
no postdefault.  If I'm reading gdbarch.sh correctly, this means that:

- we use 0 as the value in the dummy gdbarch object we use during
  startup, and

- we set this field to -1 in a newly allocated gdbarch object, and we
  report an internal error if we notice later that it still has this
  value.

If I add a postdefault, then instead of getting an internal error when
it's not initialized, we'll just drop in the postdefault value.

Is that correct?

This field should be zero for almost every architecture.  Would anyone
mind if I added a postdefault of zero?