title: CMake: Include directory for local static library
body: <p>I have a static library in my project, lets call it <code>libcommon</code>, and I am including a header file from this library <code>#include &lt;libcommon/common.h&gt;</code>, not the angular brakets, not upper quotes. How can I configure CMakeLists.txt so that it find the include?</p>
  
  <p>Assume the directory structure is like this:</p>
  
  <pre><code>-- root/
      \-- src/
      |   |-- libcommon/common.h
      |   \-- main/main.c
      \-- CMakeLists.txt
  </code></pre>
  
  <p>I tried:</p>
  
  <pre><code>include_directories (... src)
  </code></pre>
  
  <p>and:</p>
  
  <pre><code>include_directories (... ${main_SOURCE_DIR}/src)
  </code></pre>
  
  <p>but the libcommon/common.h was not found.</p>