anchor.diff:  , dbus-glib
   , gdk-pixbuf
   , cairo
  +, python2
   , python3
   , libsodium
   , postgresql
  
positive.code: , clang
  , llvmPackages
  , linux-pam
  , rdkafka
  , ...
  }:
  
  
negative.code:   dbus = attrs: {
      nativeBuildInputs = [ pkg-config ];
      buildInputs = [ dbus ];
    };
  
    expat-sys = attrs: {
      nativeBuildInputs = [ cmake ];
    };
  
    foundationdb-sys = attrs: {
  