Unity8 won't login on Ubuntu Mate 16.04

[jonnius]

Steps to reproduce:

• Get Ubuntu Mate 16.04
• Download an run the Unity8 install script
• Reboot and try to login with Unity8

Result: Stuck at LightDM (switching back to Mate works though)

If I got Marius right, we need Mesa with VC4 support (like described here).

[SohnyBohny]

Had a similar experience when I tried the same setup before:
ubports/unity8#48