Because of how nixpkgs works, all the SDL-umbrella libraries are in different folders. On a usual system, when using `sdl-config --libs`, this means that SDL_gfx would also be on the linker path. Some packages seem to depend on this being the case.
This commits needs a MAJOR audit as I oftentimes just guessed which of `$hostOffset`, `$targetOffset`, or a fixed offset should be used.