anchor.diff:  
     src = fetchurl {
       url = "https://notmuchmail.org/releases/${name}.tar.gz";
  -    sha256 = "1v0ff6qqwj42p3n6qw30czzqi52nvgf3dn05vd7a03g39a5js8af";
  +    sha256 = "1jjnhs4xs4gksvg0a9qn68rxrj41im5bh58snka2pkj20nxwmcds";
     };
   
     nativeBuildInputs = [ pkgconfig ];
  
positive.code: with stdenv.lib;
  
  stdenv.mkDerivation rec {
    version = "0.28.3";
    name = "notmuch-${version}";
  
    passthru = {
  
negative.code:       --replace '-install_name $(libdir)' "-install_name $out/lib"
    '';
  
    configureFlags = [ "--zshcompletiondir=${placeholder "out"}/share/zsh/site-functions" ];
  
    # Notmuch doesn't use autoconf and consequently doesn't tag --bindir and
    # friends
    setOutputFlags = false;
    enableParallelBuilding = true;
    makeFlags = [ "V=1" ];
  
    preCheck = let
      test-database = fetchurl {
  