For anyone interested, a new implementation was recently open-sourced. Bloomberg's timezone library including tzdata parser was part of the recent 3.0 release of the BDE C++ library. This is built on top of the previously released date/time vocabulary types.

High-level utility for performing conversions, TimeZoneUtil (doxygen):
http://bloomberg.github.io/bde/group__baltzo__timezoneutil.html

All baltzo:: component docs: http://bloomberg.github.io/bde/group__baltzo.html

All baltzo:: component code: https://github.com/bloomberg/bde/blob/master/groups/bal/baltzo

-Andrew @ Bloomberg