In mitkGPGPU.h, there's this:
#ifdef _WIN32
#include <windows.h>
#else
#include <GL/glx.h>
#include <X11/Xlib.h>
#endif
Which means you either have to be building on Windows, or building using X11. This means the build will fail for MAC OS X unless you build VTK, Qt, and MITK as an X11 application.