Comm issues shouldn't be serious, it's just not detecting clang++. Gcc should be able to compile it, or if not right now, there can be just some minor issues.
Comm is a mix of various helper libraries used throughout OT, previously a part of an old networking library running on Linux and Windows both. Most of the porting actually lies in this library, as the OT core only uses little of Windows-specific functionality - just some async IO, AFAIK.
Apart from that there aren't many other dependencies: Chromium browser, audio library (going to swap out unreliable OpenAL for FMOD), which should be all portable already.
What remains is a serious bulk of driver issues though. Both Linux and OSX drivers lag behind the Windows GPU drivers, and OT uses many new OpenGL features that a few other apps use yet. On Windows we had to report many driver bugs & wait for fixes before being able to release a build that works for majority of Win users. OSX, from what I've heard, has a
poor state of the drivers in this regard, and what's worse - we can forget about getting (relatively) prompt responses from their development team, as we are getting from AMD or Intel (haven't had many problems with Nvidia so far).
I'm afraid we'll have to invest a lot of time into workarounds for driver bugs on OSX to get it reasonably working. As a small company we can't afford it right now, so we are postponing it until our own code base is stable enough, and until our user base is wide enough that supporting minor platforms makes sense, in hopes that till then mighty Apple fixes their issues.
With Linux it's a bit different, as the support is required by our customers that use OT for special simulation projects, so it's already firmly in the plans, and we already have vendor support. But it's expected only after the Windows version matures and "proves" itself. So right now we are only loosely ensuring that everything we write and use is portable, compiling parts with gcc from time to time. The first step is actually going to be a 64-bit version on Windows, and only that will be ported & tested on other platforms.
