anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "jemalloc";
  -  version = "5.2.1";
  +  version = "5.3.0";
   
     src = fetchurl {
       url = "https://github.com/jemalloc/jemalloc/releases/download/${version}/${pname}-${version}.tar.bz2";
  -    sha256 = "1xl7z0vwbn5iycg7amka9jd6hxd8nmfk7nahi4p9w2bnw9f0wcrl";
  +    sha256 = "sha256-LbgtHnEZ3z5xt2QCGbbf6EeJvAU3mDw7esT3GJrs/qo=";
     };
  -
  -  patches = [
  -    # workaround https://github.com/jemalloc/jemalloc/issues/2091
  -    (fetchpatch {
  -      url = "https://github.com/jemalloc/jemalloc/commit/3b4a03b92b2e415415a08f0150fdb9eeb659cd52.diff";
  -      sha256 = "sha256-6AYtADREhfj93ZLk9xnXtjc6vHDU0EKLLOvLd6YdJeI=";
  -    })
  -  ];
   
     # see the comment on stripPrefix
     configureFlags = []
  
positive.code:       "je_cv_thp=no"
      ]
    ;
  
    doCheck = true;
  
  
negative.code: { lib
  , stdenv
  , fetchurl
  # By default, jemalloc puts a je_ prefix onto all its symbols on OSX, which
  # then stops downstream builds (mariadb in particular) from detecting it. This
  # option should remove the prefix and give us a working jemalloc.
  