(ldap-ldif-safe-char-regexp): New constant.

(ldap-ldif-safe-char-regexp): New constant.
(ldap-ldif-safe-init-char-regexp): Ditto.
(ldap-ldif-safe-string-regexp): Ditto.
(ldap/ldif-safe-string-p): New macro.
(ldap/ldif-insert-field): Ditto.
(ldap-modify): Use it.
(ldap-add): Ditto.
(ldap-search-basic): Consider `attrsonly' also when `attrs' is nil.
(ldap-decode-attribute): Decode only when `attr' is consp.
(ldap-delete): Bind `ret'.