the files that collide are: - /usr/lib/opengl/global/include/glxext.h - /usr/lib/opengl/global/include/glext.h
eselect-opengl and opengl-update should block each other
uhm no. Please don't mix unstable and stable packages. opengl-update is just a frontend to eselect opengl and doesn't include the header files. You have an old version of opengl-update on your system.