anchor.diff: -{ lib, stdenv, fetchurl, ncurses, pkgconfig }:
  +{ lib, stdenv, fetchurl, ncurses, pkgconfig
  +
  +# procps is mostly Linux-only. Most commands require a running Linux
  +# system (or very similar like that found in Cygwin). The one
  +# exception is ‘watch’ which is portable enough to run on pretty much
  +# any UNIX-compatible system.
  +, watchOnly ? !(stdenv.isLinux || stdenv.isCygwin) }:
   
   stdenv.mkDerivation rec {
     name = "procps-${version}";
  
positive.code:   nativeBuildInputs = [ pkgconfig ];
  
    makeFlags = [ "usrbin_execdir=$(out)/bin" ]
      ++ lib.optionals stdenv.isDarwin [ "watch" "PKG_LDFLAGS="];
  
    enableParallelBuilding = true;
  
  
negative.code:     description = "Utilities that give information about processes using the /proc filesystem";
      priority = 10; # less than coreutils, which also provides "kill" and "uptime"
      license = lib.licenses.gpl2;
      platforms = lib.platforms.unix;
      maintainers = [ lib.maintainers.typetetris ];
    };
  }
  