Add back-ndb

build/top.mk

configure

configure.in

doc/man/man5/slapd-ndb.5

doc/man/man5/slapd.backends.5

include/portable.hin

servers/slapd/back-ndb/Makefile.in

servers/slapd/back-ndb/TODO

servers/slapd/back-ndb/add.cpp

servers/slapd/back-ndb/attrsets.conf

servers/slapd/back-ndb/back-ndb.h

servers/slapd/back-ndb/bind.cpp

servers/slapd/back-ndb/compare.cpp

servers/slapd/back-ndb/config.cpp

servers/slapd/back-ndb/delete.cpp

servers/slapd/back-ndb/init.cpp

servers/slapd/back-ndb/modify.cpp

servers/slapd/back-ndb/modrdn.cpp

servers/slapd/back-ndb/ndbio.cpp

servers/slapd/back-ndb/proto-ndb.h