-no PAM (default): let configure figure out whether shadow passwords
are used, in that case xscreensaver will be installed suid to enable
checking
-"pam" option enabled: assume that PAM is able to check the password
w/o root privs; require the new pam-pwauth_suid on NetBSD for that
-"pam" option enabled; the user decides not to use pam-pwauth_suid
but sets xscreensaver suid instead (on NetBSD, or if the PAM
implementation needs it)
add a MESSAGE discussing the latter 2 options
bump PKGREVISION
