K 10
svn:author
V 3
jhb
K 8
svn:date
V 27
2011-02-04T16:32:34.988829Z
K 7
svn:log
V 327
MFC 217292:
- Retire some unused ithread priorities: PI_TTYHIGH, PI_TAPE, and
  PI_DISKLOW.  While here, rename PI_TTYLOW to PI_TTY.
- Add a macro PI_SWI() that takes a SWI_* constant as an argument and
  returns the suitable thread priority.

To preserve the KBI, I did not renumber priorities but simply removed
unused ones.

END