Hi all! I was able to get the gens-gs build working with the attached patch on top of Pierre's original. Tested the output by loading up a "Chakan: The Forever Man" ROM, seemed to work fine :) The key was this line of the Nix package definition: https://github.com/NixOS/nixpkgs/blob/master/pkgs/misc/emulators/gens-gs/default.nix#L16 Apparently gens-gs' code is so old that it's using some deprecated GTK APIs, so we have to remove the GTK_DISABLE_DEPRECATED define, etc, from GTK_CFLAGS so that the build will complete successfully. David