This ensures function name maps to C API.
Also renames Dummy type into PyObject_Opaque as the type will be
used in other units.
Part of S821-014
Change-Id: I14a2d05897480c4dbfb3f04a2fe45567d2385a7b
* Py_SetProgramName expect a *wchar_t
* Py_SetPythonhome expect a *wchar_t
* Py_Main except decoded arguments as *wchar_t
* Expose function Py_DecodeLocale
Part of T518-013
Change-Id: I3ad1df239203ecf70e5de7dfe78aed202cd21666