so... calculating the path to dojo is quite a bit more involved than what you currently have.  what if i:

* don't call my package `"dojo"`?
* configure it as `packages: [ 'dojo' ]`?
* (improperly?) use `paths` rather than `packages`?
* ... 

i'm wondering if inlining _base/configWebworker here would be the best option.  i'd want to get input from @rcgill and others to see what they think.  

* since it's code that is `has`-bracketed, it can be removed during a build (which reminds me, you'll probably need to update the default [`staticHasFeatures`](https://github.com/dojo/util/blob/1.9.1/build/buildControlDefault.js#L42-L78)) and is probably less code than trying to account for all the possible ways i might define "dojo" in a config.
* it removes the need for the `webworkerDojoConfig` global.
* you don't need to create a `importScriptsCacheBust` (or any variant of that) because by the time you would be loading anything via `importScripts`, the `cacheBust` that is in scope (defined later in this file) would be available to you.
* the webworker `getText` is essentially the same as the one defined in `if has("dom") {  ...` so there's probably a way to arrange the code to reuse that
* `fixupUrl` is already defined in here so...
* essentially you're just tweaking some `hasCache` values and overriding `injectUrl` which seems like it might be reasonable to inline here

@ssimpo what do you think about that as an idea?