Answering your questionI compiled IT myself a while ago. Scavenging the actual tools in their exact version numbers as outlined in the readme file was the most complicated part. I could find some in their exact version number (just use your favourite search engine), but I think for the linker I might have chosen a different version. I recall that
phatcode had the version that I needed. This all just depends on your search-engine-fu, so I cannot help you there.
Once you have the tools, do the following to keep it simple: Install/copy them into a sub directory called "TASM5" of the IT code directory.
Then in DOSBox, do:
mount C "Path\To\ImpulseTracker\"
C:
SET PATH=C:\TASM5\BIN\
MAKE
This will build the tracker. To build the drivers, I think you need to do:
CD SoundD~1
MWAV.BAT
I think there were some problems with that, so if it doesn't work out of the box, let me know.
All of this can be gathered from the manual and reading the error messages, though - no programming knowledge is required. You just need to be patient and actually read that stuff.
Is it basically free now as well, or even included in the source code?
All the code is released under the BSD license, so noone can stop you from building and spreading your own IT WAV Writer driver. And I doubt that Jeff Lim would still care a lot about the $20 for the IT registration these days.
Anyway, here is my compiled version of IT and some of the drivers:
http://sagagames.de/stuff/ImpulseTracker.7zAnswering your actual problemNone of that will help you with playing modules on a modern system, though, since you still require a DOS system to use IT and its driver. Rendering modules in DOSBox is still very slow.
GreaseMonkey has been working on a
C port of the IT engine over the last year. This allows using the same rendering engine as IT, but on a modern system.
Nitpickingprovide a very accurate playback of IT and S3M
IT is good, but by far not the best S3M player. For Unreal music it is arguably the best because those S3Ms were written in Impulse Tracker.
While other libraries like DUMB, libopenmpt or BASS might not be 100% accurate in every single corner case, they are all very close to the original IT output and you will most likely not find any differences when playing the Unreal or Deus Ex soundtracks in them (both soundtracks are very simple and do not require a very accurate player). So I don't think you really need to go the route of rendering the files through the IT WAV driver - the only thing you will gain from this is that you get to hear how the files might have sounded to their creators, but not how they sounded in-game: Unreal Engine's Galaxy Sound System has very limited IT playback capabilities and will thus not sound quite the same as Impulse Tracker anyway.