bpo-36775: Add _Py_FORCE_UTF8_FS_ENCODING macro (GH-13056)

Add _Py_FORCE_UTF8_LOCALE and _Py_FORCE_UTF8_FS_ENCODING macros to
avoid factorize "#if defined(__ANDROID__) || defined(__VXWORKS__)"
and "#if defined(__APPLE__)".

Cleanup also config_init_fs_encoding().
5 files changed