Ubuntu 16.10 is now in feature freeze and there is (apparently) one bug on s390x platform that prevents v3.7.3 from making it into the release in lieu of the older 3.5.6. that's a real shame, I hope someone from this list can help out.

here is the failing build log on ubuntu 16.10:
https://launchpadlibrarian.net/281969183/buildlog_ubuntu-yakkety-s390x.syslog-ng-incubator_0.5.0-1_BUILDING.txt.gz

this does build correctly on debian sid though:
https://buildd.debian.org/status/fetch.php?pkg=syslog-ng-incubator&arch=s390x&ver=0.5.0-1&stamp=1468967484

Regards,

Gil Bahat