Remove the global _Py_CheckRecursionLimit variable: it has been
replaced by ceval.recursion_limit of the PyInterpreterState
structure.
There is no need to keep the variable for the stable ABI, since
Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() were not usable
in Python 3.8 and older: these macros accessed PyThreadState members,
whereas the PyThreadState structure is opaque in the limited C API.
Use linker comment #pragma and preprocessor for re-exporting stable
API functions and variables.
Module definition file, custom build targets and entry point code
become unnecessary and can be removed.
This change also fixes missing _PyErr_BadInternalCall export on x86.
Vladimir Matveev
Victor Stinner
Inada Naoki
Nikita Nemkin
Antoine Pitrou
Martin v. Löwis