Comment 1 for bug 1580331

Yep, its the symlink thing..., dunno why postgres can't deal with them, seems very strange.

precise/trusty
GMT -> Greenwich
Zulu -> UTC

xenial
Greenwich -> GMT
UTC -> Zulu

So there is neither default which will work across the series... bummer.
http://<email address hidden> says it should default to UTC if not specified, but that's for internal db timestamps, not sure for logging.

http://stackoverflow.com/questions/26049242/postgresql-error-timezone-directory-stack-overflow also mentions to check whether it was compiled with the --with-system-tzdata flag, but dunno what the debbuild does.