gettext replacement doesn't work

[nicopace]

I've copied the soonick/pommo master branch commit 1774566 to my server.
I setted up the config, as such:

<?php die(); /* DO NOT REMOVE THIS LINE! SERIOUS SECURITY RISK IF REMOVED! */ ?>
==========================================================
Welcome to the poMMo Configuration File! From here you setup your database and
  other preferences.

IMPORTANT: This file must be named "config.php" and saved in the "root"
  directory of your poMMo installation (where bootstrap.php is).

See config.sample.php for descriptions of settings
==========================================================

[db_hostname] = <ip>
[db_username] = <user>
[db_password] = <pass>
[db_database] = <dbname>
[db_prefix] = <dbprefix>

[lang] = es
[debug] = off
[verbosity] = 3
[date_format] = 3

It finishes the installation.
When i go to login, it shows me this message:

"Php gettext module is not installed."

The server indeed doesn't have support for gettext, but i've seen that pommo includes a replacement for this module: https://github.com/soonick/poMMo/blob/master/lib/gettext/gettext.inc

Any ideas how to debug it?