anchor.diff:  
   let
   
  -  inherit (builtins)
  -    toString ;
     inherit (lib)
       concatMapStrings filterAttrs mapAttrs mapAttrsToList mkOption unique ;
     inherit (lib.types)
  
positive.code:           return EXIT_FAILURE;
          }
        '';
      in pkgs.runCommand name {} "gcc -Wall -Wextra -Werror -s -std=gnu99 -O2 ${src} -o $out";
  
    cliapp = submodule({name, ...}:
    {
  
negative.code: 
    exec = name: { user, command, ... }:
      let
        cc = "${pkgs.gcc}/bin/gcc -Wall -Wextra -Werror -s -std=gnu99 -O2";
        uid = toString config.users.users.${user}.uid;
        gid = uid;
        src = pkgs.writeText "${name}.c" ''
          #include <unistd.h>
          #include <grp.h>
          #include <pwd.h>
          #include <stdio.h>
          #include <stdlib.h>
          #include <sys/types.h>
  
  