Remove libldap dependency (not used for now)

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@free.fr>
Tune Sconstruct to build freelan on OpenWRT

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@free.fr>
Remove zlib dependency (not used directly)

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@free.fr>
Merge pull request #16 from champtar/openwrt

Openwrt build