title: Does gmcs or xbuild predefine any properties?
body: <p>I'm porting some .NET code to mono, which involves #if blocks like:</p>
  
  <pre><code>#if !MONO
  // Stuff that only works in &gt;NET
  #endif
  </code></pre>
  
  <p>I can define these things in the csproj file and set a mono build target. However, I was wondering if xbuild or gmcs predefined anything  so I know if I'm compiling on mono.</p>