Regarding repl.it, I'm not sure how active it is. Their python C port for example is 2 years since the last update. I'll ping them to see.

Regarding lua, I updated the lua vm project, and tried your fibonacci function from before in the repl

http://kripken.github.io/lua.vm.js/repl.html

Looks like in both firefox and chrome it runs in about a second in JS, which feels about the same as the time it takes in PNaCl in chrome on

http://gonativeclient.appspot.com/demo/lua