tlsdate: Support IPv6-only networks

This is based on a patch that buildroot applies to tlsdate,
originally authored by Avery Pennarun (apenwarr@gmail.com).
https://github.com/jameshilliard/buildroot/blob/master/package/tlsdate/tlsdate-0020-openssl-ipv6.patch

BUG=b:63137232
TEST=tlsdate is able to sync time on IPv6 only system

Change-Id: I8529ea54fbcc1e77f2cdc2787debbe793cd68f53
Reviewed-on: https://chromium-review.googlesource.com/717021
Commit-Ready: Ian Coolidge <icoolidge@google.com>
Tested-by: Ian Coolidge <icoolidge@google.com>
Reviewed-by: Dan Erat <derat@chromium.org>
1 file changed