title: Pass Jenkins build parameters to pipeline nodes
body: <p>I created a new Jenkins pipeline. The pipeline is (currently) parametrized with a single boolean option named <code>VAR_A</code>. My pipeline script is:</p>
  
  <pre><code>node ('windows') {
      echo "$VAR_A"
      bat 'env'
  }
  </code></pre>
  
  <p>When I manually build the project with <code>VAR_A</code> checked, "true" is echoed, as expected. The list of environment variables, however, does not show <code>VAR_A=true</code>.</p>
  
  <p>I am able to get <code>env</code> to show <code>VAR_A</code> if I wrap the call in a <code>withEnv</code> block:</p>
  
  <pre><code>node ('windows') {
      echo "$VAR_A"
      withEnv(["VAR_A=$VAR_A"]) {
          bat 'env'
      }
  }
  </code></pre>
  
  <p>I will more parameters than this, so specifying each parameter individually is not desired. <strong>Is there a way to transfer all build parameters to a node's environment?</strong></p>