I'm not really sure it's a bug with Qt Creator, it might be more with the Qt which is bundled with Qt Creator, but when I try and build a project which links against Qt (against my system libqt stuff on Ubuntu), building from within Qt Creator ends with the following:

/opt/qtcreator-2.4.82/lib/libQtDBus.so.4: undefined reference to `QMutex::unlockInternal()'
/opt/qtcreator-2.4.82/lib/libQtDBus.so.4: undefined reference to `QMutex::lockInternal()'
/opt/qtcreator-2.4.82/lib/libQtDBus.so.4: undefined reference to `QMetaCallEvent::QMetaCallEvent(unsigned short, unsigned short, void (QObject*, QMetaObject::Call, int, void*), QObject const, int, int, int*, void*, QSemaphore)'

The code I'm using doesn't use QMutex in any way directly, and I don't believe it uses DBus directly either.
It's a CMake project, and if I go back to Qt Creator 2.4 or use CMake from the terminal without using Qt Creator in any way the project builds fine.
I've tried clean builds too.

I can only assume that Qt symbols are leaking somehow from Qt Creator, and confusing CMake, which is using the Qt Creator Qt libs instead of my system ones.