* in printcol(), don't bother building an index to the linked list if
only printing one column with printscol()...
* implement -n; prevent [gu]id->name mapping in long listings.
inspired by openbsd, but does *not* imply -l by itself.
* fix sorting with -d (or mismatched types in general). (from openbsd).
* document -g. (from openbsd).
ac591fc02c