With the source code released we should have expected this. Called Arx Liberatis.
It's in its early stages at the moment, but so far the code already runs under linux using winelib. Using Wine is far from perfect and is only a temporary solution, but Arx Libertatis compiled with winelib runs much better than the original game does which uses the standard windows binaries under Wine. (mainly due to replacing GDI text rendering with Freetype) We also maintain windows compatibility, so any fixes and improvements will not be exclusive to linux users.
Expect better pathfinding AI and many other improvements.
Arx Libertatis is a source port based on the publicly released Arx Fatalis source code.
System requirements: CPU: 900 MHz
RAM: 256 MB
GPU: OpenGL 1.5-compatible
HDD: ~750 MB
AND: Arx Fatalis data files, WINE to install and patch, for localized versions you'll need to create a cfg.ini within the game dir with the following content:
and replace english with your language eg: deutsch, chinese, italiano, whatever...
You can read more about it here.