anchor.diff:    setOutputFlags = false; # it would move $out/modules, etc.
   
     buildInputs = [perl] ++
  +    optional brotliSupport brotli ++
       optional sslSupport openssl ++
       optional ldapSupport openldap ++    # there is no --with-ldap flag
       optional libxml2Support libxml2 ++
  
positive.code: , http2Support ? true, nghttp2
  , ldapSupport ? true, openldap
  , libxml2Support ? true, libxml2
  , luaSupport ? false, lua5
  }:
  
  
negative.code:     --enable-cern-meta
      --enable-imagemap
      --enable-cgi
      ${optionalString brotliSupport "--enable-brotli --with-brotli=${brotli}"}
      ${optionalString proxySupport "--enable-proxy"}
      ${optionalString sslSupport "--enable-ssl"}
      ${optionalString http2Support "--enable-http2 --with-nghttp2"}
  