requirejs - Bundling javascript files -

i have project different modules written closure functions (example of module shown below). trying optimize project, can me bundling suggestion? how bundle them single file?

1. i know requirejs these traditional closure functions , not sure if can use requirejs project not written in commonjs or amd pattern?
2. other option found concat these js files per forums not practice.

can suggest me correct way bundling these kind of files? or wrong way write modules @ first?

 var main = (function(){     //constructor     function main(){};      main.prototype.entry = function(){         alert("entry function called");     }     return main; })(); 

thanks in advance.