qmake seems to include .cpp files from INCLUDEPATH

When building the gui/analogclock example on Windows 7, it puts ../rasterwindow into the includepath in order to include rasterwindow.h, but this seems to also pick up ../rasterwindow/main.cpp, causing this to override analogclock/main.cpp.

This causes the example to show the same thing as rasterwindow ("QWindow" on a white background) instead of an analog clock