title: How to set clang as default compiler using update-alternatives
body: <p>I use Ubuntu 18.04 and I have two gcc/g++ versions which are managed using update-alternatives:</p>
  
  <pre><code>sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 100 --slave /usr/bin/g++ g++ /usr/bin/g++-7
  sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 50 --slave /usr/bin/g++ g++ /usr/bin/g++-4.8
  </code></pre>
  
  <p>I can switch compiler using this command:</p>
  
  <pre><code>sudo update-alternatives --config gcc
  </code></pre>
  
  <p>I have noticed that I have the following chain for the compiler (gcc-7/g++-7 in this case): <code>/usr/bin/cc -&gt; /etc/alternatives/cc -&gt; /usr/bin/gcc -&gt; /etc/alternatives/gcc -&gt; /usr/bin/gcc-7
  /usr/bin/c++ -&gt; /etc/alternatives/c++ -&gt; /usr/bin/g++ -&gt; /etc/alternatives/g++ -&gt; /usr/bin/g++-7</code></p>
  
  <p>I have also installed clang-8 and clang++-8 but <code>/usr/bin</code> contains only clang-8 and clang++-8, there is no clang symbolic link. How should I add clang to update-alternatives tools ?</p>