treewide replacement of stdenv.mkDerivation rec { name = "*-${version}"; version = "*"; to pname
The source code is no longer available as the repository https://github.com/EpicGames/UnrealEngine has been deleted.
This builds Unreal Engine 4 and has a wrapper to start the editor. Sadly the application requires write access to a lot of paths. I have a hack to do a symlink tree under $HOME and it works well, the UE4Editor binary just needs to be not a symlink.