Most of the commands can only be called if we have the GIL:
retrieve it.
Add a controlled type to automatically retrieve/free the GIL.
Lock every call using Py_INCREF/Py_DECREF.
Change-Id: I8989fcb3eacf6aedbb90056469536144a2795a3f
* Move PyEval_SaveThread to GNATCOLL.Python.Eval
* Move PyEval_RestoreThread to GNATCOLL.Python.Eval
* Move PyThreadState to GNATCOLL.Python
* Remove binding to PyEval_InitThreads (not needed since 3.7)
* Remove Has_Thread_Support (we assume python 3 always have thread
support)
Part of S821-014
Change-Id: I037b19be518a36600663df20d34f233c91bc4139