Move almost all private functions of Include/cpython/fileutils.h to
the internal C API Include/internal/pycore_fileutils.h.
Only keep _Py_fopen_obj() in Include/cpython/fileutils.h, since it's
used by _testcapi which must not use the internal C API.
Move EncodeLocaleEx() and DecodeLocaleEx() functions from _testcapi
to _testinternalcapi, since the C API moved to the internal C API.
This reverts commit ea251806b8.
Keep "assert(interned == NULL);" in _PyUnicode_Fini(), but only for
the main interpreter.
Keep _PyUnicode_ClearInterned() changes avoiding the creation of a
temporary Python list object.
This change is strictly renames and moving code around. It helps in the following ways:
* ensures type-related init functions focus strictly on one of the three aspects (state, objects, types)
* passes in PyInterpreterState * to all those functions, simplifying work on moving types/objects/state to the interpreter
* consistent naming conventions help make what's going on more clear
* keeping API related to a type in the corresponding header file makes it more obvious where to look for it
https://bugs.python.org/issue46008
Victor Stinner
Eric Snow