title: Using a compile-time environment variable to configure RestApplicationPath
body: <p>As stated in the documentation of <a href="https://github.com/ArcBees/GWTP/wiki/Rest-Dispatch" rel="nofollow">rest-dispatch</a>, the rest application path must be configured in the GIN module  via a constant, here "/api/v1": </p>
  
  <pre><code>public class DispatchModule extends AbstractGinModule {
     @Override
     protected void configure() {
         RestDispatchAsyncModule.Builder dispatchBuilder = 
                 new RestDispatchAsyncModule.Builder();
         install(dispatchBuilder.build());
         bindConstant().annotatedWith(RestApplicationPath.class).to("/api/v1");   
     }
  }
  </code></pre>
  
  <p>I would like to make the "/api/v1" constant be resolved at compile time, based on an environment variable set by the build system depending on the target environment (prod, dev, etc...), and on other criteria (the build artifact major version...).</p>
  
  <p>The problem is I do not manage to rely on a compile time variable.
  Neither TextResource/CssResource nor GWT's <a href="http://www.gwtproject.org/doc/latest/DevGuideCodingBasicsDeferred.html" rel="nofollow">deferred binding</a> won't help here, since <code>GWT.create()</code> cannot be used in GIN module. Another option I considered is using a custom Generator, but this seems to be too complex for this very simple need. </p>
  
  <p>How do you solve this problem ?</p>