title: Is it possible to configure sub-project dependencies in SBT based on a `SettingKey`?
body: <p>I am trying to accomplish something like this:</p>
  
  <pre><code>lazy val customFlag = settingKey[Boolean]("My custom flag")
  
  lazy val depOne    = project ...
  lazy val depTwo    = project ...
  
  lazy val myproject = project
    .settings(
      customFlag := false)
    .dependsOn(if (customFlag) depOne else depTwo)
  </code></pre>
  
  <p>The idea being, that I could then use <code>set customFlag := true</code> in the sbt console in order to change whether project <code>myproject</code> depends on sub-project one or two.</p>
  
  <p>I have a hunch at this point that the answer is that this is not possible. But it would be nice to get confirmation or an alternative to accomplish something similar.</p>