Updated to latest release: 0.20.2 => 0.20.3

hi! i'm trying to put as much hardware specific code into if_rge_hw.c to hopefully make it easier to keep whole hardware-specific routines in sync with openbsd.

Fix the close-on-fork fd test: add an EVFILT_USER to the second kqueue and
trigger it, then confirm that the parent sees the read-event while the child
does not. This shouldn't be fragile because the EVFILT_READ will be readable
as of the very first scan in the child, so things would have to go pretty wrong
for it to appear but not beat the 3-second timer to being observed.