Detect graphics library vendor
With this change we are now able to check if the used driver is GLVND or non-GLVND. This information is useful for example when steam-runtime-system-info is failing to find GLX ICDs. When this will happens we will be able to know if this is due to the use of non-GLVND driver or if there is something unexpected.
Edited by Ludovico de Nittis