* python/python-internal.h (PyGILState_Ensure): New define.
(PyGILState_Release): Likewise.
(PyEval_InitThreads): Likewise.
(PyThreadState_Swap): Likewise.
(PyEval_InitThreads): Likewise.
* python/python.c (_initialize_python): Initialize threads.
Release GIL.
(eval_python_from_control_command): Acquire GIL.
(python_command): Likewise.
* python/python-internal.h (make_cleanup_py_restore_gil):
Declare.
* python/python-utils.c (py_gil_restore): New function.
(make_cleanup_py_restore_gil): Likewise.