Add section on troubleshooting Gazebo on Wayland

[iche033]

Related issue: gazebosim/gz-sim#1934

Running Gazebo on Wayland may result in a crash with an error msg about missing current gl context. Updated the troubleshooting guide with a section on Wayland with the solution mentioned in gazebosim/gz-sim#1934 (comment) about unsetting the WAYLAND_DISPLAY env var and making gz use XWayland

[mabelzhang]

Oh this is interesting. @clalancette was testing Gazebo with Wayland, but in Docker. We ended up using xhost + local: before docker run. Maybe this is different, or maybe it's a less permissive way?

[iche033]

hmm I think the xhost cmd allows docker container to access X on host. It probably means the docker args for passing the DISPLAY, xauth, etc didn't work? I've done the xhost cmd before but saw that it's not safe according to http://wiki.ros.org/docker/Tutorials/GUI

[mabelzhang]

It probably means the docker args for passing the DISPLAY, xauth, etc didn't work? I've done the xhost cmd before but saw that it's not safe according to http://wiki.ros.org/docker/Tutorials/GUI

🤔 Yeah... it's not safe. Will look into it... Thanks!