I get this deprecation warning whenever I use Mu in my projects with Node 0.6+. I tried manually changing the import in compiler.js from sys to util and everything seemed to work fine.
I'm seeing the same thing. Would you accept a pull request for the relatively simple changes necessary to resolve this? Also, would you then update it in npm?
Submitted a pull request to resolve this: #21
Fixed in master. Thanks for bringing this issue up. Master is now the v2 branch, please check the API changes.