[php-src] Issue #7998: ldap_search not working with base=NULL after php7.1

Issue: https://github.com/php/php-src/issues/7998 Author: dab18 ### Description The following code: ```php <?php $ds = ldap_connect(); // <-- URI from /etc/openldap/ldap.conf ldap_set_option($ds, LDAP_OPT_PROTOCOL_VERSION, 3); $sr = ldap_search($ds, NULL, "(uid=dab)", array("dn")); // <-- BASE from /etc/openldap/ldap.conf $entry = ldap_first_entry($ds, $sr); var_dump($entry); ``` Resulted in this output: ``` Warning: ldap_search(): Search: No such object in test.php on line 5 ``` But I expected this output instead: ``` resource(6) of type (ldap result entry) ``` /etc/openldap/ldap.conf: BASE c=ru URI ldap://localhost slapd.log: slapd[14091]: conn=4230791 op=0 SRCH base="" scope=2 deref=0 filter="(uid=dab)" slapd[14091]: conn=4230904 op=0 SRCH base="c=ru" scope=2 deref=0 filter="(uid=dab)" related bug&commit: https://bugs.php.net/bug.php?id=77958 https://github.com/php/php-src/commit/5d2fe48785b6d24102ff53e78631cba7f2aefbef ### PHP Version PHP 8.0.12 ### Operating System gentoo