Red Hat gave Linus some stock prior to their IPO, which was hardly required but a pretty nice gesture.
I don't know of any other public examples of a company making stock grants to developers of major building blocks of their ecosystem, but they might be out there. GitHub is under no obligation, but I think they owe as much to Linus as Red Hat did in 1999.
But this makes me wonder if any of the founders have written Linus a check to show their thanks. Or maybe after they IPO. :-)
(Obviously they've done a ton on their own.)