That cleared the sdl2 warning for me (and provided me the motivation to add my first unstable package!). TY!
Still having cursor weirdness (and no app icon) but I think I probably messed up something to do with wayland.
Are you using the unstable channel? SDL2 stuff was cleared up for me with this tweak to the package: https://github.com/NixOS/nixpkgs/commit/db6be866d53a65f0081792b05cb37c2a21e5ef89
Discussion
Yea, I am running Wayland too and had to add some settings in home manager for my cursor. Only issue I still have with gossip is the scrolling feels very different than my other apps. But hard to track down why.
I have avoided the home-manager rabbit hole, but would take another stab at it just for gossip...
I increased the inertial scrolling to 1.5 and it's much better, imo. Scrolling via touchpad, mainly.
I avoided hm for as long as I could too. It still feels very heavy, but has iron’d out a few quirks like this.