title: #ifdef DEBUG with CMake independent from platform
body: <p>I am using CMake for building my projects on Windows (Visual Studio) as well as on Linux machines(gcc). I'd like to mark some code as "debugging only", like with</p>
  
  <pre><code>#ifdef DEBUG
  //some logging here
  #endif
  </code></pre>
  
  <p>The question is: what compiler definition is available on all platforms in the CMake "Debug" build type? DEBUG seems not to exist. (I want to have the logging or whatever only when the build type is Debug.)</p>