anchor.diff:  
     configureFlags = [
       "--localstatedir=/var"
  +    "--with-libcap=${libcap.dev}"
       "--with-libtool"
       "--with-libxml2=${libxml2.dev}"
       "--with-openssl=${openssl.dev}"
  
positive.code: { stdenv, lib, fetchurl, openssl, libtool, perl, libxml2
  , enablePython ? false, python3 ? null
  , enableSeccomp ? false, libseccomp ? null, buildPackages
  }:
  
negative.code:     "--without-idn"
      "--without-idnlib"
      "--without-lmdb"
      "--without-libjson"
      "--without-pkcs11"
      "--without-purify"
      "--with-randomdev=/dev/random"
  