title: Conditionally use 32/64 bit reference when building in Visual Studio
body: <p>I have a project that builds in 32/64-bit and has corresponding 32/64-bit dependencies.  I want to be able to switch configurations and have the correct reference used, but I don't know how to tell Visual Studio to use the architecture-appropriate dependency.</p>
  
  <p>Maybe I'm going about this the wrong way, but I want to be able to switch between x86 and x64 in the configuration dropdown, and have the referenced DLL be the right bitness.</p>