As the cross development SDK for AmigaOS 4 isn’t released yet, the idea to do an unofficial guide to setting up a cross-compiler was born. This document will describe how to do just that. This document also expects you to have some knowledge of Linux or Cygwin, as these are the platforms used in this document.
Maybe this is why Duke Nukem Forever is taking so long, it still being compiled for the Amiga.
It looks like this requires you to be running in a Linux host environment. I think there was a C compiler called vbcc or something like that for the Amiga. Later, they added a beta version that would run in an MSDos window on Windows, and you could cross compile from the Microsoft environment. The link could be found on Aminet.