title: Verbose output for cmake command
body: <p>I would like to know if there is any way to debug a <code>cmake</code> process that forcing the command to print mode details about how variables are getting some value. For example, I see</p>
  
  <pre><code>-- Boost version: 1.63.0
  -- Boost version: 1.63.0
  -- Found the following Boost libraries:
  --   system
  --   filesystem
  --   timer
  --   chrono
  </code></pre>
  
  <p>And I would like to know where does that version is checked and found.</p>
  
  <p>I have added <code>set(CMAKE_VERBOSE_MAKEFILE ON)</code> in the first line of <code>CMakeLists.txt</code> prior to running <code>cmake ..</code>. However, I don't see any verbose message.</p>
  
  <p>I am looking for some thing like <code>set -x</code> in bash programming.</p>