================================================================================
Copy /usr/local/etc/ldap.conf.dist to /usr/local/etc/ldap.conf, then edit
/usr/local/etc/ldap.conf in order to use this module.  Add a line similar to
the following to /etc/pam.conf on 4.X, or create an /etc/pam.d/ldap on 5.X
and higher with a line similar to the following:

login   auth    sufficient      /usr/local/lib/pam_ldap.so
================================================================================