anchor.diff:      owner = "MariaDB";
       repo = "mariadb-connector-c";
       inherit rev;
  -    sha256 = "00898eda42dce5a432336fbfdbac71e7e3af81799b1afcd70667be88aada7749";
  +    sha256 = "40749572ddae702b7522dd0bed864f3b5cadb6a4fec798fd4aacb6213d0d0685";
     };
   
     nativeBuildInputs = [
  
positive.code:   postInstall = ''
      ln -sv mariadb_config "$out"/bin/mysql_config
      ln -sv mariadb "$out"/include/mysql
      ln -sv libmariadb.so "$out"/lib/libmysqlclient.so
    '';
  
    meta = with stdenv.lib; {
  
negative.code: }:
  
  let
    rev = "3f356c0598ad4785e9b4eff23e03fd662a701070";
    date = "2017-07-07";
  in
  stdenv.mkDerivation rec {
    name = "mariadb-connector-c-${date}";
  