title: $$PWD no longer working in Qt Creator 2.6
body: <p>I have a project (<a href="https://github.com/waddlesplash/qtfastjson" rel="nofollow">https://github.com/waddlesplash/qtfastjson</a>) that has a .pri file that uses qmake's <code>$$PWD</code> variable. This works fine in all tested versions of qmake, but in Qt Creator 2.6, the files are not displayed in the project tree (but it compiles properly).</p>
  
  <p>Here's the PRI:</p>
  
  <pre><code>QT += core
  INCLUDEPATH += $$PWD
  
  HEADERS += $$PWD/QtFastJson.h \
      $$PWD/QtFastJsonObject.h
  
  SOURCES += $$PWD/QtFastJson.cpp \
      $$PWD/QtFastJsonObject.cpp
  </code></pre>
  
  <p>which is included from a .pro: <code>include(../src/QtFastJson.pri)</code>.</p>
  
  <p>If the <code>$$PWD</code> variables are removed and replaced with relative paths, the files show in the tree.</p>