Proposal for updating src/timezone

My proposal is the have the following directory structure

.../src/timezone - Would have only PostgreSQL specific code

.../src/timezone/tznames - would be unaltered from current (optionally this could be removed)

.../src/timezone/iana - would contain unaltered code and data from IANA

The .../src/timezone/data directory would be removed.

In doing this, any future updates to the IANA code should be trivial to incorporate into the postgres tree.

Reasons for change.

1. The current timezone code is based upon, according to the comments, version 2010c from IANA. IANA's latest code is version 2014e and there are substantial changes between those versions (as well as 35 intermediate versions ... Yes, IANA changes and updates the code regularly and frequently)

2. The current timezone data has a few entries that are not properly handled by any pre-2013 code so an update of some sort is needed anyway.

3. The latest code from IANA compiles with GCC using a kitchen sink array of warning options without any generated warnings. This should alleviate any  concerns about not accepting any code unless it's warning free. In case anyone is interested, the GCC options are: -Dlint -g3 -O3 -fno-common -fstrict-aliasing  -Wall -Wextra -Wbad-function-cast -Wcast-align -Wcast-qual -Wformat=2 -Winit-self -Wmissing-declarations -Wmissing-noreturn -Wmissing-prototypes -Wnested-externs -Wno-address -Wno-cast-qual -Wno-format-nonliteral -Wno-sign-compare -Wno-sign-conversion -Wno-type-limits -Wno-unused-parameter -Woverlength-strings -Wpointer-arith -Wshadow -Wstrict-prototypes -Wsuggest-attribute=const -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure -Wtrampolines -Wwrite-strings

Aspects of change that I'm not happy with.

1. I would have liked to recommend 2 sub-directories underneath .../src/timezone/iana named "code" and "data", but unfortunately have to suggest untarring both the code and data files directly into the iana directory. The reason for this is that the IANA code does not compile using the IANA Makefile unless the script yearistype.sh is present and that script is currently present in the data tar file, not the code tar file. And that unfortunately means that splitting the IANA code and data into different directories would violate the objective of being able to deposit the files unaltered into postgres. 

2. Depositing the IANA code unaltered would also deposit some "junk" files into the directory. The files would mainly consist of man pages and html files containing documentation for the timezone code. The extra files would consume approximately 500 kilobytes above what's actually needed, but otherwise wouldn't have any adverse effects.

Thank you for reading this proposal,

John Cochran

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