Instead of using #if, this now uses SFINAE to detect the presence of the
glibc extensions to set IPv6 nameserver addresses. It's also possible
that this fixes some bugs that have always been there, but never checked
because we don't have a way to unit-test explicit name servers.
To that effect, this commit adds a manual unit test that mimics the BIND
tool "dig". When running:
./qdnslookup qt-project.org any @dns.google
it printed for me:
; <<>> QDnsLookup 6.6.0
;; status: NoError
;; QUESTION:
;qt-project.org IN ANY
;; ANSWER:
qt-project.org 3600 IN MX 10 mx.qt-project.org
qt-project.org 3600 IN NS ns14.cloudns.net
qt-project.org 3600 IN NS ns11.cloudns.net
qt-project.org 3600 IN NS ns12.cloudns.net
qt-project.org 3600 IN NS ns13.cloudns.net
qt-project.org 3600 IN A 52.18.144.254
qt-project.org 3600 IN TXT "v=spf1 mx ip4:193.209.87.4 include:spf.protection.outlook.com ~all"
;; Query time: 241 ms
;; SERVER: 2001:4860:4860::8844#53
strace confirms the DNS queries were sent to the correct address.
Change-Id: I3e3bfef633af4130a03afffd175d56a92371ed16
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
