Support slice numbers in device names. The syntax is `<driver name>
[<unit number>] ['s' <slice number>] [<partition letter>]'. Only
`['s' <slice number>]' is new here. The slice number defaults to 0
so that there is no change in the output from config if this new
feature is not used.
Replace some magic disk numbers by `dk' slice and label macros.
mkswapconf.c:
Improve the output formatting:
Generate <> style includes.
Print minor numbers in hex so that slice numbers are easy to see and edit.
Print the rootdev and dumpdev names in comments like the swapdev names.
Peter Dufault
Bruce Evans
Garrett Wollman
Rodney W. Grimes