Attempting to Load Multiple ROMs Crashes the Program

[Vivit-R]

When I attempt to open any ROM via the File menu while another ROM is already open, the program crashes, printing the following message to stderr:

Cannot make QOpenGLContext current in a different thread
Aborted (core dumped)

Version Information:

0.8.1
Branch: heads/0.8.1
Revision: a16d5f3

I am running the Qt version in X on Ubuntu 18.04.4 LTS.

[endrift]

Duplicate of #1642, but I'm unsatisfied with the fix for that (it caused #1686)

[endrift]

Fixed in 74edd96 on Windows and GLX. Still need to test on macOS and EGL.

[endrift]

Additional fixes in cb7f150, should work everywhere now, potentially excluding EGL/Wayland.