title: Flash Builder conditional compilation problem
body: <p>how can I do the following in a Flex project?</p>
  
  <pre><code>package{
  
  #ifdef BAR
      class Foo{
          ...implementation of Foo....
      }
  
  #else
      class Foo{
          ...alternative implementation of Foo
      }
  #endif
  }
  </code></pre>
  
  <p>if I try to do it with the following compiler statements
      -define CONFIG::BAR,true
      -define CONFIG::NOBAR,false</p>
  
  <p>and program it this way:</p>
  
  <pre><code>package{
  
  CONFIG::BAR{
      class Foo{
          ...implementation of Foo....
      }
  }
  
  CONFIG::NOBAR{
      class Foo{
          ...alternative implementation of Foo
      }
  }
  }
  </code></pre>
  
  <p>then flash builder gives me a compile error:</p>
  
  <pre><code>1018: Duplicate class definition: Main
  </code></pre>
  
  <p>how to resolve that?</p>