title: Automatically rebuild dependencies in Qt Creator
body: <p>Qt Creator (4.6.1) is driving me nuts. My application is split into 3 parts:</p>
  
  <ul>
  <li>the app</li>
  <li>the library</li>
  <li>a unit tests app</li>
  </ul>
  
  <p>When I change a file within the library and rebuild the application, the compiler does not recompile the library but links with the old version of the library.</p>
  
  <p>Also, when I change the library, recompile it and then compile the app, no compilation takes place because it uses the cached app.</p>
  
  <p>Is there a setting to change that? Here's my project file:</p>
  
  <pre><code>TEMPLATE = subdirs
  
  SUBDIRS += \
      app \
      lib_mylib \
      tests
  
  app.depends = lib_mylib
  tests.depends = lib_mylib
  </code></pre>
  
  <p>The lib is built as a static library:</p>
  
  <pre><code>TEMPLATE = lib
  TARGET = mylib
  CONFIG += staticlib
  </code></pre>