indicating an unhandled "command". ERESTART is -1, which can lead to
confusion. ERESTART has been moved to -3 and EPASSTHROUGH has been
placed at -4. No ioctl code should now return -1 anywhere. The
ioctl() system call is now properly restartable.
independent z8530 driver. When that driver is updated, the local copy
of those files may be removed. From Bill Studenmund.
Compiler warnings fixed by me.