I don't recall what support policy, if any, was decided regarding the
various distributions, but I believe at least one commit
(https://code.wireshark.org/review/#/c/14041/) was reverted due to the
adverse affect of breaking Wireshark builds on RHEL6.
Now that RHEL6 has reached the end of production phase 1[1], I don't know if
we want to move forward with that patch (or other patches?). I don't follow
other distributions that closely and don't know what versions of the various
packages they supply, so while I think it would be reasonable to no longer
worry about supporting RHEL6, perhaps there are other distributions that
would be the new bottleneck?
(RHEL7, by the way, ships with autoconf-2.69.)
- Chris
[1]: https://access.redhat.com/support/policy/updates/errata