up to 9.8.4-P2; fixes CVE-2013-2266

regardless https://kb.isc.org/article/AA-00871 saying 9.8.4-P2 is still affected
see also https://kb.isc.org/article/AA-00879

bind-9.8.4-P2/CHANGES:
3516. [security] Removed the check for regex.h in configure in order to disable
regex syntax checking, as it exposes BIND to a critical flaw in libregex on
some platforms. [RT #32688]