Installation:
perl Makefile.PL
make
sudo make install

This version of Apache2::AuthTicketLDAP overloads several methods from
Apache::AuthTicket, including:

===============================================================================
Plan to submit upstream
===============================================================================
dbi_connect()
 a) passwordless local connections
 b) AutoCommit via TicketDBAutoCommit option
 c) a couple of Informix-specific options (ISOLATION and LOCK MODE)

_update_ticket_timestamp()
 a) TicketThreshold: Only update the database when a ticket timestamp is at
 least X seconds old. Reduces database updates.

===============================================================================
Needs some work to support configuration, but could be submitted upstream
===============================================================================
hash_for()
 a) Use Digest::SHA instead of MD5

===============================================================================
Will not submit upstream due to using cache
===============================================================================
is_hash_valid()
 a) Use a SQL SELECT statement result cache

fetch_secret()
 a) Use a SQL SELECT statement result cache
 b) Change DESC LIMIT 1 to SELECT FIRST 1. This is an Informix-ism.
 c) Don't listen to SQL::Abstract's quoting of the version number, which 
 Informix doesn't like.
 d) FIXME: Informixisms should be ifdef'd for Driver eq Informix. Also, SELECT
 FIRST is only supported in Informix 10+

check_credentials()
 a) Use LDAP
 b) Use LDAP Entry cache