title: Using $(SolutionDir) when running template via TextTransform.exe
body: <p>I'm trying to get our T4 templates to run at build time, without adding dependencies on the Visual Studio Modeling SDK. I've successfully used a variant of the batch file shown <a href="https://stackoverflow.com/a/3041089">here</a>, but I now have a problem in that my .tt files use the <code>$(SolutionDir)</code> variable to reference other projects (and thus are now not compiling).</p>
  
  <p>What is the best way to handle this? What have other people done? (Hard-coding absolute paths is not an option)</p>
  
  <p>EDIT:
  I see there's the <code>-a</code> argument that can be passed to TextTransform.exe, is it possible to use this to define <code>$(SolutionDir)</code>?</p>