Allegro is a cross-platform library mainly aimed at video game and multimedia programming. It handles common, low-level tasks such as creating windows, accepting user input, loading data, drawing images, playing sounds, etc. and generally abstracting away the underlying platform. However, Allegro is not a game engine: you are free to design and structure your program as you like.
Homepage: http://liballeg.org/
lists.liballeg.org/allegro-developers
This list is for the people currently working on Allegro. You can use this address if you need to contact the developers, for example to submit some new code that you have written or to report a bug.
lists.liballeg.org/allegro-security
Mailing list to privately report security issues with Allegro.