Update libgl-gl4es-pyra package to depend on package glx-diversions and provide gl4es as a glx alternative
This merge request updates the libgl-gl4es-pyra package to
- depend on package glx-diversion - this sets up the mesa gl libraries on the system to allow alternative libraries to replace them.
- Add postinst/postrm scripts to libgl-gl4es-pyra that register the gl4es libGL.so.1 as an alternative for 'glx' at package install time, and removes the alternative when the package is removed.
This allows the default libGL.so.1 on the system to be switched to the gl4es version via running;
sudo update-alternatives --set glx /usr/lib/arm-linux-gnueabihf/gl4es
to revert to having mesa as the default libGL.so.1 run; update-alternatives --set glx /usr/lib/mesa-diverted
Since the switching of libGL.so.1 is done using the debian alternatives and dpkg-diverts it should be fully compatible with the standard mesa packages and not cause any problems with future package updates by Debian.