title: Cannot find g++ build and debug active file when trying to add configuration
body: <p>I am running the latest vscode installed with .deb on ubuntu 20.04 on a laptop.
  C/C++ extension v 1.9.7 (latest) was installed.</p>
  <p>I followed everything in the tutorial in
  <a href="https://code.visualstudio.com/docs/cpp/config-linux" rel="nofollow noreferrer">https://code.visualstudio.com/docs/cpp/config-linux</a></p>
  <p>and I am stuck in the debugging as I cannot choose g++ build and debug active file in launch.json</p>
  <p>task.json is auto generated as below</p>
  <pre><code>    {
      &quot;version&quot;: &quot;2.0.0&quot;,
      &quot;tasks&quot;: [
          {
              &quot;type&quot;: &quot;cppbuild&quot;,
              &quot;label&quot;: &quot;C/C++: g++ build active file&quot;,
              &quot;command&quot;: &quot;/usr/bin/g++&quot;,
              &quot;args&quot;: [
                  &quot;-fdiagnostics-color=always&quot;,
                  &quot;-g&quot;,
                  &quot;${file}&quot;,
                  &quot;-o&quot;,
                  &quot;${fileDirname}/${fileBasenameNoExtension}&quot;
              ],
              &quot;options&quot;: {
                  &quot;cwd&quot;: &quot;${fileDirname}&quot;
              },
              &quot;problemMatcher&quot;: [
                  &quot;$gcc&quot;
              ],
              &quot;group&quot;: {
                  &quot;kind&quot;: &quot;build&quot;,
                  &quot;isDefault&quot;: true
              },
              &quot;detail&quot;: &quot;compiler: /usr/bin/g++&quot;
          }
      ]
  }
  </code></pre>
  <p>And when I tried to select Run &gt; Add Configuration... and choose C++ (GDB/LLDB),
  I see no drop down list for &quot;g++ build and debug active file&quot;
  <a href="https://i.stack.imgur.com/j31hh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/j31hh.png" alt="enter image description here" /></a></p>
  <p>Any suggestions?</p>