o The parse tree is now passed to the alias, match and defaults functions.
o The nss API has been changed so that the nss parse() function returns
a pointer to a struct sudoers_parse_tree which will be filled in
by the getdefs() and query() functions.
in a per-nss list of userspecs and defaults instead of using separate
lookup and list functions. This makes it possible to have a single
implementation of the code for sudoers lookup and listing.
queue functions. This includes a private queue.h header derived
from FreeBSD. It is simpler to just use our own header rather than
try to deal with macros that may or may not be present in various
queue.h incarnations.
