nis_ypldap_enable and nis_ypldap_flags.
Also add an entry on ypldap(8) that it is a feature ready and
appears on FreeBSD 11.0.
Requested by: rodrigc
Relnotes: Yes
ypldap -- Intended to be a drop-in replacement for ypserv, gluing in a
LDAP directory and thus providing support for users and groups stored in
LDAP for the get{pw,gr}ent family of functions.