Really cool news! I skipped picking this up in GOG's christmas sale, but I think I might need to go grab it now.
Is this the game that GOG.com paid the developers to make a new compatibility patch, which ended up being GOG-exclusive? I seem to recall that being a sore point with folks who bought it elsewhere, so this is a nice resolution.
And it's always great news to hear about a game being open-sourced. Even better insurance of future compatibility and cross-platform support. I look forward to being able to play it in Linux or on a cell phone, probably by next week at the rate they usually port these things.