title: Testing a parameter passed through the /D command line switch fails in Inno Setup
body: <p>I call <code>ISCC /DENABLE_SIGNING=1 MyFile.iss</code>, and in MyFile.iss I have:</p>
  
  <pre><code>#if ENABLE_SIGNING == 1
  SignedUninstaller=yes
  SignTool=mysigntool
  #endif
  </code></pre>
  
  <p>ISPP fails with an error exactly at the line with <code>#if ENABLE_SIGNING == 1</code>:</p>
  
  <blockquote>
    <p>[ISPP] Operator not applicable to this operand type.</p>
  </blockquote>
  
  <p>But if I've defined ENABLE_SIGNING in the MyFile.iss instead, it goes fine. This code passes without errors:</p>
  
  <pre><code>#define ENABLE_SIGNING 1
  
  #if ENABLE_SIGNING == 1
  SignedUninstaller=yes
  SignTool=mysigntool
  #endif
  </code></pre>
  
  <hr>
  
  <p><strong>Edit</strong></p>
  
  <p>Also, there is another problem, when I use <code>/DENABLE_SIGNING=0</code>, testing <code>#if ENABLE_SIGNING</code> succeeds, while if I use <code>#define ENABLE_SIGNING 0</code>, the check fails (meaning evaluates to false), as it should.</p>