Commit 6035d557c4 added a hard requirement for Net::DNS > 0.78 in order
to allow the reclimit test to be run.  This is not the first test which
has issues with certain versions of Net::DNS (the others being chain,
dnssec, nsupdate, resolver, serve-stale, statistics and xfer).

Relying on packaged versions of Net::DNS is not an acceptable solution
on some of the platforms we support, e.g. CentOS 7 ships with version
0.72, which was released in 2012.

One possible solution is to ship a recent version of Net::DNS in our
repository/tarballs, but as we are currently trying to reduce the amount
of external code being bundled with BIND, this idea was rejected.

Another solution is to write a script which would fetch and build an
appropriate version of Net::DNS, subsequently installing it in a manner
which would allow it to be used when system tests are run (e.g. by
overriding certain environment variables).  Such a script could
obviously perform a Net::DNS version check beforehand and exit
immediately if the version found is determined to be sufficiently
recent.