fix size in memset() parameter. Thanks max.
add bio(4) support
xref mpt(4)
xref bio(4)
mpt(4): added bio(4) support.
Add execvpe in one more place to explain its last argument.
Call character '0' 'NUL' instead of 'null'.
show "sd0" instead of "mpt0" for volume device name
include vendor/product/rev info for volumes and their disks
no longer needed
implement BIOCDISK_NOVOL
Pull readability changes from OpenBSD/luna88k.

- prepare and use unpack_attr() function to get fg and bg from attribute
- use proper variable names to clarify meanings

Tested on LUNA-II with 8bpp framebuffer.
Put dumb optimizations to avoid conditionals in putchar drawing loops.

~10% improvements of time cat results on LUNA-II 8bpp framebuffer.
PR/44218 - David Young -- add "type" subcommand to change a partition type
for BIOCDISK_NOVOL, set bd_disknovol=true for any disk not associated with a volume
for BIOCDISK_NOVOL, when setting bd_disknovol=false, also set bv_volid
the RPi wiki had the values for VCPROPTAG_SET_CURSOR_INFO and
VCPROPTAG_SET_CURSOR_STATE swapped - now they actually work
thanks jmcneill@ for having the right idea
add hardware cursor support
make global variables static
also, make cursor test pattern red/green to highlight RGB vs. BGR
Remove never used usb locators