nss-pam-ldapd is a fork of nss_ldap that uses a daemon (nslcd) to
connect to the LDAP server, instead of going directly from PAM/NSS.
This improves performance and separation, and increases security
if you connect to LDAP with a password, since only the nscd daemon
needs to know the password, not every user of PAM/NSS.
This commit will be followed by a commit to NixOS which enables the
use of the nslcd daemon.
