> How can I pass a -j8 flag to make for all builds? The following ~/.nixpkgs/config.nix file seems to do the trick: { replaceStdenv = { stdenv, overrideSetup }: stdenv // { mkDerivation = args: stdenv.mkDerivation (args // { makeFlags = (if args ? makeFlags then args.makeFlags else []) ++ ["-j8" "-l8"]; }); }; } Peter