[vtkusers] Many VTK build tests fail when run from Jenkins/Bamboo or VNC display, even when DISPLAY is set to good opengl-enabled display

[Ben Boeckel]

On Sat, Dec 23, 2017 at 04:57:00 +1030, John wrote:
> ps Re using VNC, for me it was an almost total failure, so i quickly
> gave up and switched to sending the tests to my main Xorg/nvidia head.
> 
> Under vnc,the tests fail with an error message which says:

What if you set `MESA_GL_VERSION_OVERRIDE=3.2` in the environment?
Something causes a request of a compat profile when on VNC. This tells
Mesa to claim it has a compat profile at 3.2 (this profile is
technically missing old functions, but VTK doesn't need them anyways).

>     Preferred profile: compat (0x2)

You can see that a compat profile was requested here.

--Ben