Compiling VTK with X11-xcb on Ubuntu 20

I cloned a vtk nightly-master repo, created a build folder and ran ccmake ../vtk
Now I see that it cannot find X11-xcb related stuff:

X11_xcb_util_INCLUDE_PATH
X11_xcb_util_LIB
X11_xcb_icccm_INCLUDE_PATH
X11_xcb_icccm_LIB
X11_xcb_xfixes_INCLUDE_PATH
X11_xcb_xfixes_LIB

If I go ahead and compile VTK without the proper paths for X11, I can still compile VTK but when I run a Python example that apparently requires X11, VTK segfaults as soon as the window opens. The error is X connection to NAME broken (explicit kill or server shutdown) where NAME is a weird set of special chars.

However, I have already installed libx11-xcb-dev package on Ubuntu 20. I’ve got also xorg and openbox. I assume I only need X11 client, not server.

If I understand correctly, in the INCLUDE_PATH, I should put folders that have header .h files and for LIB, the .so libs. I did find that the libs are under /usr/lib/x86_64-linux-gnu but I’m not sure where are the header files.

Even when I set the LIB paths, it doesn’t seem to change anything.

I assume here that the segfault error is related to not found X11 but I could be wrong.