It was made by Volition (Micro$oft did Free Lancer). I think there is already a linux version. the existing C++ code has DEFINEs for mac OS and linux.

C++ to Pascal conversion is usually quite straight forward. It's when you start doing pointer arithmatic it get's complicated.

If you want a good place to start on C++ to Pascal conversion check out

http://www.delphi-jedi.org/APICONVTEAMS:244282
http://www.drbob42.com/headconv/

As well as the Quake 2/3 projects.