postgresql/src/timezone

This is a PostgreSQL adapted version of the timezone library
from:

	ftp://elsie.nci.nih.gov/pub/tzcode*.tar.gz

The data files under data/ are an exact copy of the latest data set
from

	ftp://elsie.nci.nih.gov/pub/tzdata*.tar.gz

Since time zone rules change frequently in some parts of the world,
we should endeavor to update the data files before each PostgreSQL
release.