anchor.diff:  { stdenv, fetchurl, fetchgit, openssl, zlib, pcre, libxml2, libxslt, expat
  -, gd, geoip
  +, gd, geoip, luajit
   , rtmp ? false
   , fullWebDAV ? false
   , syslog ? false
   , moreheaders ? false
  -, echo ? false }:
  +, echo ? false
  +, ngx_lua ? false }:
   
   with stdenv.lib;
   
  
positive.code:     ++ optional syslog "--add-module=${syslog-ext}"
      ++ optional moreheaders "--add-module=${moreheaders-ext}"
      ++ optional echo "--add-module=${echo-ext}"
      ++ optional (elem stdenv.system (with platforms; linux ++ freebsd)) "--with-file-aio";
  
  
  
negative.code: 
    buildInputs =
      [ openssl zlib pcre libxml2 libxslt gd geoip
      ] ++ optional fullWebDAV expat
        ++ optional ngx_lua luajit;
  
    LUAJIT_LIB = if ngx_lua then "${luajit}/lib" else "";
    LUAJIT_INC = if ngx_lua then "${luajit}/include/luajit-2.0" else "";
  
    patches = if syslog then [ "${syslog-ext}/syslog-1.5.6.patch" ] else [];
  
  