Revisiting Re: BUG #8532: postgres fails to start with timezone-data >=2013e

Hey all -- so I know that Gentoo Linux is likely the only platform this
bug occurs under, but i got annoyed enough with it that I decided to
write a patch to fix this issue once and for all (or at least, help keep
it from happening).

That thread in question actually dealt with crashing on startup in
postgresql-9.1 and earlier, but all versions including the latest still
suffer from the inability to load timezone data via the pg_timezone_*
tables if /usr/share/zoneinfo contains filesystem loops.

To that end, the following helps resolve this issue by ensuring
single-level filesystem loops are detected and skipped. The top half of
the patch only applies to postgresql-9.1 and earlier, while the second
half applies to all versions.

(hopefully the patch attached properly)

Regards,
Ian