A basic Apache handler module that uses ETL.  This is just designed
to show you how the API should be used in an Apache module.

The handler just parses a template, builds up a set of variables,
executes the template and finally hands the resulting brigade off to
the output filters.  In this case the environment handed off to the
template consists of an 'env' hash that contains the environment of
the Apache server.  There's an env.etl template that shows you how
to make use of those variables from the template.

To compile this just do something like:

$ apxs -c -letl-0 mod_template_example.c

Then copy the resulting .so into your apache install's modules dir
and add something like this to httpd.conf to load the module:

LoadModule template_example_module modules/mod_template_example.so

And within a directory block add something like:

AddHandler template-example .etl

Then you can drop env.etl into the corresponding directory on your
filesystem, restart Apache and you should be able to view it via a
web browser.  The result should be similar to the printenv CGI that
Apache distributes.