Move creation of a tuple for var-positional parameter out of _PyArg_UnpackKeywordsWithVararg(). Merge _PyArg_UnpackKeywordsWithVararg() with _PyArg_UnpackKeywords(). Add a new parameter in _PyArg_UnpackKeywords(). The "parameters" and "converters" attributes of ParseArgsCodeGen no longer contain the var-positional parameter. It is now available as the "varpos" attribute. Optimize code generation for var-positional parameter and reuse the same generating code for functions with and without keyword parameters. Add special converters for var-positional parameter. "tuple" represents it as a Python tuple and "array" represents it as a continuous array of PyObject*. "object" is a temporary alias of "tuple".
Miscellaneous source files for the main Python shared library