gh-103092: Ensure _ctypes.c static types are accessed via global state

[neonene]

This sets in place the ctypes_state *st = GLOBAL_STATE() statements to make the coming PRs smaller. Suggested by @encukou: #113630 (comment)

cc @erlend-aasland

• Issue: Isolate Stdlib Extension Modules #103092

[erlend-aasland]

See also ongoing work by @aisk in #113620. Perhaps you could coordinate your efforts?

[encukou]

@erlend-aasland, do you want to review these two PRs?
If you merge one I'll be happy to resolve the conflicts on the other one.

[erlend-aasland]

@erlend-aasland, do you want to review these two PRs? If you merge one I'll be happy to resolve the conflicts on the other one.

Sure, I'll get to it later today.

[neonene]

Done. I'll update this after #113620 is merged.

[neonene]

I think this is ready for review. Sorry for mistakenly wiping out old commits (from web).

Actual diff with a1ade06:

--- Modules/_ctypes/_ctypes.c
+++ Modules/_ctypes/_ctypes.c
@@ -128,13 +128,6 @@
-static PyTypeObject UnionType_Type;
 static PyTypeObject Union_Type;
 static PyTypeObject Struct_Type;
 static PyTypeObject Simple_Type;
 
 ctypes_state global_state = {
     .PyCStgDict_Type = &PyCStgDict_Type,
-    .PyCStructType_Type = &PyCStructType_Type,
-    .UnionType_Type = &UnionType_Type,
-    .PyCPointerType_Type = &PyCPointerType_Type,
-    .PyCArrayType_Type = &PyCArrayType_Type,
-    .PyCSimpleType_Type = &PyCSimpleType_Type,
-    .PyCFuncPtrType_Type = &PyCFuncPtrType_Type,

[erlend-aasland]

Thanks, Victor!

[vstinner]

I merged this change which is a good start for futher work. I closed my similar duplicated (less complete) PR.