anchor.diff:    preBuild = ''
       substituteInPlace config.mk \
         --replace "/usr/local" ""
  +    substituteInPlace config.mk \
  +      --replace "WITH_WEBSOCKETS:=no" "WITH_WEBSOCKETS:=yes"
  +
     '';
   
     meta = {
  
positive.code: { stdenv, fetchurl, openssl, libuuid, cmake }:
  
  stdenv.mkDerivation rec {
    pname = "mosquitto";
  
negative.code:     sha256 = "1imw5ps0cqda41b574k8hgz9gdr8yy58f76fg8gw14pdnvf3l7sr";
    };
  
    buildInputs = [ openssl libuuid libwebsockets ]
      ++ stdenv.lib.optional stdenv.isDarwin cmake;
  
    makeFlags = [
  