Building QtCreator with Qt5 -- cannot find declarative

Hi, I am trying to build QtCreator from the source code. I have qt5 on my machine, freshly installed from ppa, and when I execute qmake -r in the src folder, I get the following error message: Project ERROR: Unknown module(s) in QT: declarative I tried to compile the master branch and the 2.6 branch. I tried to google the solution and the only thing that I found is that declarative was renamed into quick a while back, but people say that QtCreator 2.6.1 should be compilable with Qt5. Am I doing something wrong? How do I solve this problem?