but do not assume any entopy is gathered. It can be enabled using an
IOCTL again if the user desires.
Note that the mix function uses xor, so at worse an attacker can twiddle
bits in the pool, but not into a known state assuming it started as
an unknown.
Over the next few days (thank goodness for long weekends) I'll be hunting
down device drivers and adding hooks to gather entropy from many devices,
and adding the conf.c changes to the various port's device structs to
define major numbers for /dev/random and /dev/urandom.