title: LGTM config file with custom package
body: <p>I’m new to <a href="https://lgtm.com" rel="nofollow noreferrer">LGTM</a>. I like the idea of checking code quality, so I want to try it out on a project I follow a bit. The project mostly contains known packages, but also has some self-compiled code.</p>
  <p>According to <a href="https://lgtm.com/help/lgtm/analysis-faqs#dont-use-git-clone" rel="nofollow noreferrer">https://lgtm.com/help/lgtm/analysis-faqs#dont-use-git-clone</a>, I should use the following method:</p>
  <pre class="lang-sh prettyprint-override"><code>$ curl -L https://github.com/axios/axios/archive/v0.18.1.tar.gz --output v0.18.1.tar.gz
  </code></pre>
  <p>I don’t know if that package follows LGTM’s example for C++ which is as follows (it comes from <a href="https://lgtm.com/help/lgtm/cpp-extraction" rel="nofollow noreferrer">https://lgtm.com/help/lgtm/cpp-extraction</a>):</p>
  <pre class="lang-yaml prettyprint-override"><code>extraction:
    cpp:
      prepare:
        packages: 
          - libboost-all-dev
          - bison
        configure:
          command:
            - ./bootstrap
            - ./configure --with-modules=&quot;&quot; --without-lua
  </code></pre>
  <p>The problem I have is how and where do I put this custom package in the build configuration? I don’t know the package so for now I’ll use <code>package_a</code> as an example.</p>
  <p>Normal workflow for building should be:</p>
  <pre class="lang-sh prettyprint-override"><code>$ curl -L https://github.com/developer/package_a/archive/package_a_v0.1.1.tar.gz --output package_a_v0.1.1.tar.gz
  $ tar -xvzf package_a_v0.1.1.tar.gz -C package_a
  $ cd package_a &amp;&amp; sudo ./waf configure build install &amp;&amp; cd ..
  </code></pre>
  <p>I’m unable to figure out what part is <code>prepare</code>, if it is a <code>package</code> or not, <code>configure</code> or <code>index</code> (not mentioned in the example above, but it is on this page: <a href="https://lgtm.com/help/lgtm/lgtm.yml-configuration-file#example-lgtm.yml-file" rel="nofollow noreferrer">https://lgtm.com/help/lgtm/lgtm.yml-configuration-file#example-lgtm.yml-file</a>).</p>
  <p>Is this the only step (to create a package), or are there multiple steps (e.g., in the form of some commands under <code>prepare</code> and some other under <code>configure</code>, etc.)?</p>