anchor.diff:  
     mainCfg = config.services.httpd;
   
  -  httpd = pkgs.apacheHttpd;
  +  httpd = pkgs.apacheHttpd.override { mpm = mainCfg.multiProcessingModule; };
   
     getPort = cfg: if cfg.port != 0 then cfg.port else if cfg.enableSSL then 443 else 80;
   
  
positive.code:           "Options appended to the PHP configuration file <filename>php.ini</filename>.";
        };
  
        maxClients = mkOption {
          default = 150;
          example = 8;
  
negative.code:       # Other modules.
        "ext_filter" "include" "log_config" "env" "mime_magic"
        "cern_meta" "expires" "headers" "usertrack" /* "unique_id" */ "setenvif"
        "mime" "dav" "status" "autoindex" "asis" "info" "dav_fs"
        "vhost_alias" "negotiation" "dir" "imagemap" "actions" "speling"
        "userdir" "alias" "rewrite" "proxy" "proxy_http"
      ]
      ++ (if mainCfg.multiProcessingModule == "prefork" then [ "cgi" ] else [ "cgid" ])
      ++ optional enableSSL "ssl"
      ++ extraApacheModules;
  
  