title: msbuild: set a specific preprocessor #define in the command line
body: <p>In a C++ file, I have a code like this:</p>
  
  <pre><code>#if ACTIVATE
  #   pragma message( "Activated" )
  #else
  #   pragma message( "Not Activated")
  #endif
  </code></pre>
  
  <p>I want to set this ACTIVE define to 1 with the msbuild command line.</p>
  
  <p>It tried this but it doesn't work:</p>
  
  <pre><code>msbuild /p:DefineConstants="ACTIVATE=1"
  </code></pre>
  
  <p>Any idea?</p>