release lock as early as possible; deferring referral checking in searches may reduce the amount of dynamic entry generation

document missing feature; avoid the risk of returning argv in an inconsistent state when an error occurs

	draft-ietf-ldapbis-syntaxes
Add uniqueMemberMatch approximate support
Add uniqueMemberMatch indexing support

"subordinate objects must be deleted first" as the "not supported"
language implies some feature of LDAP is not implemented in slapd(8).

in accordance with LDAPprep)