Using SO_REUSEPORT allows to quickly kill the server via SIGINT, SIGTERM or SIGKILL and start it again, without waiting for the OS to close the socket by timeout. Closes #804 (for the second time)

9f1b4a8 Document gfx_use_x11xrandr_wm, update FAQ - Dune-jr e62f61f Add inp_grab as a possible fix to mouse input i... - Dune-jr

Similarly to the console, this could let players see more chat history without having to use a nerdy console. I assume it should only work when +show_chat is active, and not save state.