Loading resources from custom URL

I have an application that maps URLs to controllers and actions such as:

/myApp/controller1/action1

The ExtJS resources, however, are accessible via a different URL, e.g.:

/myApp/static/app

/myApp/static/ext

How do I configure ExtJS to look for its resources in these other URLs?

Btw, I am loading ExtJS using the bootstrap.js file generated by Sencha cmd.  This tries to load a lot of resource files, but all from relative location to the URL of the controller/action.  In version 4, I could set custom paths on the Loader, but this does not seem to work in version 5 anymore.