gh-76785: Improved Subinterpreters Compatibility with 3.12 (gh-115424)

For the most part, these changes make is substantially easier to backport subinterpreter-related code to 3.12, especially the related modules (e.g. _xxsubinterpreters). The main motivation is to support releasing a PyPI package with the 3.13 capabilities compiled for 3.12.

A lot of the changes here involve either hiding details behind macros/functions or splitting up some files.

1 files changed, 13 insertions, 0 deletions

diff --git a/Modules/_interpreters_common.h b/Modules/_interpreters_common.h
new file mode 100644
index 0000000..5661a26
--- /dev/null
+++ b/Modules/_interpreters_common.h
@@ -0,0 +1,13 @@
+
+#define _RESOLVE_MODINIT_FUNC_NAME(NAME) \
+    PyInit_ ## NAME
+#define RESOLVE_MODINIT_FUNC_NAME(NAME) \
+    _RESOLVE_MODINIT_FUNC_NAME(NAME)
+
+
+static int
+ensure_xid_class(PyTypeObject *cls, crossinterpdatafunc getdata)
+{
+    //assert(cls->tp_flags & Py_TPFLAGS_HEAPTYPE);
+    return _PyCrossInterpreterData_RegisterClass(cls, getdata);
+}