Durandal is already dependent on requirejs, see here
{
"name": "Durandal",
"version": "2.2.0",
"dependencies": {
"jquery": "^1.9.1",
"knockout": "^3.4.0",
"requirejs": "^2.1.11",
"requirejs-text": "^2.0.12"
}
}
, "requirejs": "~ 2.2.0" bower.json, bower.json , . .