What is really necessary?

I have installed PostGreSQL and developed a system based on it.

The system is written in Object Rexx and runs on eComStation.  I
converted it from a previous DB2 system that I had developed.

Now I want to distribute my system to customers.  I don't want to
distribute documentation, language features, etc., just what's necessary
to run the database.

I am wondering - what elements are necessary for running?

I have 2 main folders  - pgsql  and PGSData

The structure is as follows:

pgsql

  bin
  doc
  include
  jdbc
  lib
  man
  pljava
  share
  sql

PGSData

  base
  global
  PG_clog
  pg_log
  pg_subtrans
  pg_tblspc
  pg_xlog

Several of these folders have sub-folders.

Which of the above can I delete and still have a working system?

Thanks,

John