since -ldb includes a bogus snprintf().
o Add forward refs for struct mbuf and struct rtentry for Digital UNIX.
o Reorder some functions in snprintf.c to fix -Wall
o Add missing includes to fix more -Wall
where an alias may be used before it is defined. Only turned on for visudo
and testsudoers.
o Add --disable-authentication option that makes sudo not require
authentication by default. The PASSWD tag can be used to require
authentication for an entry. We no longer overload --without-passwd.
the main loop. This allows auth routines to differentiate between
initialization that happens once vs. setup that needs to run each time
through the loop.
