cd ~ && git clone https://github.com/kvspb/nginx-auth-ldap.git cp -R /usr/ports/www/nginx ~/nginx-ldap
edit ~/nginx-ldap/Makefile add CONFIGURE_ARGS --add-module=path_to_http_auth_ldap_module
HAS_CONFIGURE= yes CONFIGURE_ARGS+=--prefix=${ETCDIR} \ .... --user=${WWWOWN} --group=${WWWGRP} \ --add-module=path_to_http_auth_ldap_module
install modified port
cd ~/nginx-ldap make install clean
cd ~ && git clone https://code.google.com/p/nginx-auth-ldap/
in nginx source folder
./configure --add-module=path_to_http_auth_ldap_module make install