core/pkgs/by-name/nc/ncurses/packages.nix

{ ... }:
res: pkgs: super:

with pkgs; {
  ncurses5 = ncurses.override { abiVersion = "5"; };
  ncurses6 = ncurses.override { abiVersion = "6"; };
  ncurses = if stdenv.hostPlatform.useiOSPrebuilt then null else callPackage ./. { };
}