This directory contains various server extensions and tools, for use with
the Greenplum server. Some of them are copies of various open source
projects (e.g. pljava), some are proprietary Greenplum-only modules.

The philosophy is that each module within extensions/ can be built
independently, without checking out the whole main repository. You should
use pg_config, autoconf and other such tools to set up the paths to the
server sources, and any other libraries needed to build the module. You should
not reference releng makefiles or the ext-directory directly, all such paths
should be passed to the autoconf script or Makefile instead.

When you add a module here, put the glue that's required to build the module
as part of the main build into the top-level Makefile or extensions/Makefile.
If the module requires a lot of setup, you can create a separate
extensions/Makefile.<module> file to contain it.