[php-src] Issue #7992: Refactor standard/dns.c into dns.c, dns_unix.c and dns_win32.c

Issue: https://github.com/php/php-src/issues/7992 Comment Author: cmb69 This comment confuses me. The implementation of the gethostby*() function looks reasonable; the implementation of the dns_*() functions appears to be the actual issue, since back then they have been implemented in dns_win32.c as full PHP functions, which already caused issues, because it's indeed easily overlooked that their implementation in dns.c is not the only one available. Improving this makes sense to me. I wouldn't know, though, to which "new winxp+ API" the comment is referring. Maybe it's about using DnsQueryEx instead of DnsQuery, but the former is only available as of Windows 8/Server 2012.