Passing custom build options to closure when building with stealjs

Question

I am using JavascriptMVC to build an app with StealJS build functionality. This is my build.js:

load("steal/rhino/rhino.js");
steal('steal/build').then('steal/build/scripts','steal/build/styles',function(){
    steal.build('evi2/scripts/build.html',{to: 'mylovelyapp'});
});

This is working fine. However I would love to use Google Closures @define syntax to change a few variables on build time. While it would be perfectly simple to modify steals steal/build/scripts/scripts.js, I would obviously much prefer to pass the --define flags somewhere in my build-script or in my project files.

Any ideas on how to achieve this would be highly appreciated.