I wish to share my research on getting OpenGL to work on Mali GPU. I realize Armbian focuses on server images, but I suppose many people would be interested nevertheless. I have a Banana Pi Pro and an Orange Pi PC, which both have a compatible GPU. Perhaps it will work on other boards as well.
Here are the commands I used to get OpenGL to work.
# install GLX Gears, mesa GL and GLU libraries
apt-get -y install mesa-utils
# install development tools
apt-get -y in