How to compile node.js c++ module for all platforms in the cloud?

Question

Node.js

Suggested algorithm of actions: We
send the module for testing in Travis CI, if the module has successfully built and passed all the tests, we send the publication to `node-pre-gyp` to the Amazon cloud. Thus, we get the assembled module for Linux.
We repeat the algorithm on AppVeyor and get a module for Windows.
I don’t see a way to get a module for OS X.
And in general, all of the above is a rough theory - does it somehow correspond to reality or should we forget about it, raise a bunch of virtual machines and build without automating the process?