* Add _PyRuntime.pre_initialized: set to 1 when Python
is pre-initialized
* Add _Py_PreInitialize() and _Py_PreInitializeFromPreConfig().
* _PyCoreConfig_Read() now calls _Py_PreInitialize().
* Move _PyPreConfig_GetGlobalConfig() and
_PyCoreConfig_GetGlobalConfig() calls from main.c to preconfig.c
and coreconfig.c.
Calling _PyRuntime_Initialize() after _PyRuntime_Finalize() now re-initializes
_PyRuntime structure. Previously, _PyRuntime_Initialize() did
nothing in that case.
* _PyPathConfig_ComputeSysPath0() now returns 0 if argv is empty.
* Cleanup also _PyPathConfig_ComputeSysPath0() code: move variables
definitions closer to where they are used.
At Python initialization, the current directory is no longer
prepended to sys.path if it has been removed.
Rename _PyPathConfig_ComputeArgv0() to
_PyPathConfig_ComputeSysPath0() to avoid confusion between argv[0]
and sys.path[0].
Python initialization now fails if decoding pybuilddir.txt
configuration file fails at startup.
_PyPathConfig_Calculate() now reports memory allocation failure and
decoding error on decoding pybuilddir.txt content from
UTF-8/surrogateescape.
The last parameter of _Py_wreadlink(), _Py_wrealpath() and
_Py_wgetcwd() is a length, not a size: number of characters including
the trailing NUL character.
Enhance also documentation of error conditions.
The function has no return value.
Fix the following warning on Windows:
python\ceval.c(180): warning C4098: 'PyEval_InitThreads':
'void' function returning a value
