title: How to create a C #define for a certain target using CMake?
body: <p>I feel a little stupid right now. After recently converting a few smaller projects to use CMake, I decided to also get rid of a few "Platform_Config.h" files. These files contain a few preprocessing directives like <code>#define USE_NEW_CACHE</code> and control compilation.</p>
  
  <p>How would I 'convert' these defines to be controlled with CMake? Ideally by using these "cache" variables the user can easily edit.</p>