Re: 21.4.{17,18} configure.in and ldap

If `eldap.c' line numbers are the same as in upstream 21.4, reference to `_ber_pvt_opt_on' are created by *some* of `ldap_set_option' calls. Did not try to provide for such an ldap headers. Would like to see c preprocessor output for that build configuration. What ldap interface symbol expands to such a reference? Or to try to compile and link exactly that code, and see what libraries are required. This is certainly cleaner than explicit checks for symbols that are non necessarily for explicit use at all. This is how going to patch `configure.{in,ac}'.