The Doomsday Engine is an enhanced Doom source port for the Windows, Mac OS X, and Linux platforms. It is based on the source code of id Software's Doom and Raven Software's Heretic and Hexen. The Doomsday Engine and the associated ports of Doom, Heretic and Hexen have been under development since 1999.
(Taken from: http://dengine.net/dew/index.php?title=Doomsday_Engine)
Source code is available at sourceforge: http://sourceforge.net/project/showfiles.php?group_id=74815&package_id=7...
So it would be very nice if you make this portable