According to Raygun support, Linux is not supported and only Windows is supported for C++ clients. This seems odd to me personally as I believe all of the heavy lifting on the client end is done by Google's Breakpad, which does support Linux (with a different implementation strategy). I don't think it would be that much work to use the sending utilities provided by the Linux variant of Breakpad.
Even if this is not possible, I don't see why the documentation wouldn't at least include this limitation. None of your promotional material or documentation seems to include any platform limitations. The section on C++ support at the very least should specify that only Windows is supported if only Windows is supported.