Nitpick: better/cleaner to make it a tunable, doesn't make sense to have it
as r/w sysctl.
Feel free to change it once the patch gets into -current. I've sent my
patchset off, and cannot change this right now.
maybe I am mistaken but I think that without TUNABLE_INT declaration or
TUNABLE_INT_FETCH/getenv_int call the sysctl variable won't be set from kernel
environment, so this sysctl will be effectively useless.