title: How to check if a string contains a given substring?
body: <p>I need to find out if string contains a given substring.</p>
  
  <p>For example, if I'm looking for the substring <code>ABC</code> in a string like this:</p>
  
  <pre><code>S := 'ABC String';
  </code></pre>
  
  <p>I should get result True, whilst for the following string I should get result False:</p>
  
  <pre><code>S := 'DEF String';
  </code></pre>
  
  <p>How to check if a string contains a substring in InnoSetup ?</p>