During PostX Gnu/Linux RC2, I hit the following issue with RunIT-QT Browser.

QOpenGLWidget: Failed to create context
QXcbIntegration: Cannot create platform OpenGL context, neither GLX nor EGL are enabled
QOpenGLWidget: Failed to create context
QXcbIntegration: Cannot create platform OpenGL context, neither GLX nor EGL are enabled
QOpenGLWidget: Failed to create context
composeAndFlush: makeCurrent() failed

At this point, it was clear that I had forgotten something. The browser still started
but produced a transparent window without its elements. Luckily, the fix was as easy as:

sudo apt-get install libgl1-mesa-dri libgl1-mesa-glx

If you encounter a similar issue please make sure that you have the above packages
installed.