FOVE's public software release only supports Windows (7 and later).
Internally, we have Mac and Linux builds, though they are not at 100% feature parity with the Windows builds. Large portions of the software integrate directly with the OS, and not all components of the system are fully ported yet. For example, we do not yet have direct mode support outside of windows, and thus run in extended mode, which increases latency.
If you need a Mac or Linux build for a specific reason other that you just prefer a given OS, please contact the support portal and we may be able to work with you to get you a custom software release that suits your needs.
Update (April 2020): we've implemented Vulkan support on linux which improves the state of things significantly. This is expected to be released in the next major release.