> -.Fn powerhook_establish "void (*fn)(int why, void *a)" "void *arg"
> +.Fn powerhook_establish "void (*fn)(void *a, int why)" "void *arg"

I don't suppose there was any practical way to avoid the wholesale
reversal of argument order? Is that for consistency with the FreeBSD
usage? I guess that is worth something, and it could be seen as a
benefit of our "single integrated source tree" that we actually have
the ability to do rototills like this--but I see no joy in this for
any systems integrator who has some sources maintained outside of
the tree.... :/

-Chap