Add KASSERT_WARN

[bdrewery]

Summary

KASSERT_WARN is for adding KASSERTS where the impact is unknown but it makes
sense to check for the condition. It is expected that the use would
eventually be changed to a full KASSERT.

[ngie]

sys/kern/kern_shutdown.c

617

Should "fatal" be boolean?

627–628

I would update the comment here to add in "fatal".

sys/sys/systm.h

91

Existing style(9) bugs in the macro with a space missing between exp and msg?

[bdrewery]

sys/kern/kern_shutdown.c

617

I'm not sure. I almost went with boolean but am unclear on its acceptance in kernel code.

[emaste]

sys/kern/kern_shutdown.c

617

style(9) now mentions boolean, and for new code I believe we should use it.