anchor.diff:      "-X github.com/trezor/blockbook/common.buildDate=unknown"
     ];
   
  +  tags = [ "rocksdb_6_16" ];
  +
     preBuild = lib.optionalString stdenv.isDarwin ''
       ulimit -n 8192
     '' + ''
       export CGO_LDFLAGS="-L${stdenv.cc.cc.lib}/lib -lrocksdb -lz -lbz2 -lsnappy -llz4 -lm -lstdc++"
  -    packr clean && packr
  +    buildFlagsArray+=("-tags=${lib.concatStringsSep " " tags}")
  +    buildFlagsArray+=("-ldflags=${lib.concatStringsSep " " ldflags}")
     '';
   
     subPackages = [ "." ];
  
positive.code: { lib, stdenv
  , buildGoModule
  , fetchFromGitHub
  , packr
  , pkg-config
  , bzip2
  , lz4
  
negative.code: 
  buildGoModule rec {
    pname = "blockbook";
    version = "0.3.6";
    commit = "5f8cf45";
  
    src = fetchFromGitHub {
      owner = "trezor";
      repo = "blockbook";
      rev = "v${version}";
      sha256 = "1jb195chy3kbspmv9vyg7llw6kgykkmvz3znd97mxf24f4q622jv";
    };
  
    vendorSha256 = "0d17qaqn33wi7lzw4hlym56d9v4qnmvs6plpm5jiby2g5yckq0mz";
  
    nativeBuildInputs = [ pkg-config ];
  
    buildInputs = [ bzip2 lz4 rocksdb snappy zeromq zlib ];
  
  