title: Unable to customise the build directory for Qt Creator/qmake
body: <p>I've got problem trying to specify the build directory (the directory that is to store all the files prior to copying them to the DESTDIR path). </p>
  
  <p>I've got the following values in my .pro file:</p>
  
  <pre><code>DESTDIR  = E:/Development/project/build/core/debug
  OUT_PWD  = E:/Development/project/build/core/debug
  OBJECTS_DIR = $$DESTDIR/.obj
  MOC_DIR = $$DESTDIR/.moc
  RCC_DIR = $$DESTDIR/.qrc
  UI_DIR = $$DESTDIR/.ui
  </code></pre>
  
  <p>Now, all the files eventually end up in that location, however during build, the compiler is always using the "E:/Development/build/MinGW_32bit-Debug/src/core" folder (note the missing project path). This is annoying, because I want to use the /Project/build directory as this location (which is not tracked in my git repo).</p>
  
  <p>Ideally, I'd like this path to be: <code>E:\Development\project\build\src\core\debug</code>. </p>
  
  <p>The reason I want to do this is that the build process has the same location to include the compiled libs from (it's a subdirs project). </p>
  
  <p>I've had a look in the <code>Tools &gt; Options &gt; Build &amp; Run &gt; General</code> settings, and the default build directory is: <code>build/build-%{CurrentProject:Name}-%{CurrentKit:FileSystemName}-%{CurrentBuild:Name}</code></p>
  
  <p>I've had a look in my project.pro.user file, and found the following line:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;value type="QString" key="ProjectExplorer.BuildConfiguration.BuildDirectory"&gt;E:/Development/build/MinGW_32bit-Debug&lt;/value&gt;
  </code></pre>
  
  <p>However I'm unable to change this value. If I edit this line in the file directly, as soon as I open Qt Creator again, the change has reverted back.</p>
  
  <p>Is this a Qt Creator thing, or is it a qmake thing? Would I better off using a different build system such as CMake?</p>