Well, this isn't really an tool or utility, but for a while I have been trying to port Voxlap (the engine behind Ace of Spades) to Linux (and by extension anything that supports SDL). https://github.com/Ericson2314/Voxlap-Port I discussed this a bit on IRC, but thought i'd make a thread on the forums for good measure.
I had heard of Voxlap long before, but after discovering Ace of Spades I was decided to do this. It was a good way to learn some C, and I might even be able to help the team port Ace of Spades. Now of course, the team in in the midst of doing a full rewrite, but i figure this is still useful to anyone else who might want to use Voxlap in the future, and maybe even with Ace of spades as a stopgap until 1.0 is ready.
Anyways enough storytelling. I am now getting pretty close to finishing the port, but a little help would go a long way. For example If by any chance the team has replaced bits of Voxlap's inline assembly with C(++), that would help tremendously with porting as different compilers treat inline assembly in vary different ways. Alternatively if anybody wants to tackle a section of inline assembly, and either rewrite so gcc will understand, or replace it with c, that would also be great. I don't know whether converting or removing inline assembly will get to a finished port faster, so i've made a git branch for each method to work on both concurrently.
Anyways, whether or not this makes it into AoS, I'd love to see it through. And I was hoping other people here might be interested too.