re: kernel stack usage

[matthew green <mrg%eterna.com.au@localhost>]

glad to see this effort and the clean up already!

ideally, we can break the kernel build if large stack consumers
are added to the kernel.  i'd be OK with it being default on,
with of course a way to skip it, and if necessary it can have
a whitelist of "OK large users."

> 1264    cdioctl at cd.c:1204
> 1248    uvm_swap_stats at uvm_swap.c:726

i think we can ignore these two.  they're both going to be
early in the stack so very unlikely to be problematic.


.mrg.