parsers: use PyVarObject_HEAD_INIT The macro changed slightly in Python 3, introducing curly brackets that somehow confuse Clang into issuing a ton of compiler warnings. Using PyVarObject_HEAD_INIT makes these go away. It's worth noting that the code is identical: the 2nd argument to PyVarObject_HEAD_INIT is assigned to the ob_size field and is inserted immediately after "PyObject_HEAD_INIT(type)" is generated. Compilers are weird.