This directory holds third party libraries as git submodules.

If the directories are empty, the makefile based build will try
to use system libraries instead.

To set up the third party modules for building from git:

	$ git submodule init
	$ git submodule update

Then after each pull (to make sure they're up to date):

	$ git submodule update

Do NOT edit files in the submodule checkouts unless you know what you're doing.