this was causing filedesc work to be very painful.
In order to make this work split out sigio definitions to thier own header
(sigio.h) which is included from proc.h for the time being.
for the raidctl device.
Select a more conservative default for the permissions for /dev/raidctl
since the operations are performed using ioctl() not read() and write().
Submitted by: kris
Reviewed by: scottl
