title: Cross-compiling - retrieve target CPU and version
body: <p>I'm cross-compiling for VxWorks using cmake. When I run cmake the first time I have to provide informations about compiler, target OS etc..</p>
  
  <p>In the cross-compile dialogue there are three target system settings I set:</p>
  
  <ol>
  <li><strong>Operating System</strong></li>
  <li><strong>Version</strong></li>
  <li><strong>Processor</strong></li>
  </ol>
  
  <p><em>(followed by compiler etc.)</em></p>
  
  <p>While I can retrieve the first one using <code>CMAKE_SYSTEM_NAME</code>, i can't get the version and the processor.
  Both return an empty string.</p>
  
  <p>Here's an example:</p>
  
  <pre><code>MESSAGE("CMAKE_SYSTEM_PROCESSOR:   ${CMAKE_SYSTEM_PROCESSOR}")
  MESSAGE("CMAKE_SYSTEM_VERSION:   ${CMAKE_SYSTEM_VERSION}")
  </code></pre>
  
  <p><strong>Output:</strong></p>
  
  <pre><code>CMAKE_SYSTEM_PROCESSOR:   
  CMAKE_SYSTEM_VERSION:  
  </code></pre>
  
  <p>My Cmake Version is <em>2.8.10.2</em> and target OS is VxWorks (if this matters - compiler are WindRiver GNU).</p>
  
  <p>How can I get the version and processor I've set in the beginning? Or is this impossible if I cross-compile to an OS that's unknown to cmake?</p>
  
  <p><em>(Btw. Compiling works fine)</em></p>