diff --git a/py313/_curses_panel.c b/py313/_curses_panel.c
index bbbb62c..c8acd93 100644
--- a/py313/_curses_panel.c
+++ b/py313/_curses_panel.c
@@ -10,10 +10,6 @@ static const char PyCursesVersion[] = "2.1";
 
 /* Includes */
 
-// clinic/_curses_panel.c.h uses internal pycore_modsupport.h API
-#ifndef Py_BUILD_CORE_BUILTIN
-#  define Py_BUILD_CORE_MODULE 1
-#endif
 
 #include "Python.h"
 
diff --git a/py313/_cursesmodule.c b/py313/_cursesmodule.c
index 6405c3d..fa922eb 100644
--- a/py313/_cursesmodule.c
+++ b/py313/_cursesmodule.c
@@ -100,10 +100,6 @@ static const char PyCursesVersion[] = "2.2";
 
 /* Includes */
 
-#ifndef Py_BUILD_CORE_BUILTIN
-#  define Py_BUILD_CORE_MODULE 1
-#endif
-
 #include "Python.h"
 
 /* This function declaration was moved from pycore_structseq.h file to adapt
diff --git a/py313/clinic/_curses_panel.c.h b/py313/clinic/_curses_panel.c.h
index c8788c4..7abe173 100644
--- a/py313/clinic/_curses_panel.c.h
+++ b/py313/clinic/_curses_panel.c.h
@@ -5,7 +5,30 @@ preserve
 #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
 #  include "pycore_runtime.h"     // _Py_SINGLETON()
 #endif
-#include "pycore_modsupport.h"    // _PyArg_UnpackKeywords()
+
+// Export for 'math' shared extension
+PyAPI_FUNC(PyObject * const *) _PyArg_UnpackKeywords(
+    PyObject *const *args,
+    Py_ssize_t nargs,
+    PyObject *kwargs,
+    PyObject *kwnames,
+    struct _PyArg_Parser *parser,
+    int minpos,
+    int maxpos,
+    int minkw,
+    PyObject **buf);
+#define _PyArg_UnpackKeywords(args, nargs, kwargs, kwnames, parser, minpos, maxpos, minkw, buf) \
+    (((minkw) == 0 && (kwargs) == NULL && (kwnames) == NULL && \
+      (minpos) <= (nargs) && (nargs) <= (maxpos) && (args) != NULL) ? (args) : \
+     _PyArg_UnpackKeywords((args), (nargs), (kwargs), (kwnames), (parser), \
+                           (minpos), (maxpos), (minkw), (buf)))
+
+// Export for '_heapq' shared extension
+PyAPI_FUNC(void) _PyArg_BadArgument(
+    const char *fname,
+    const char *displayname,
+    const char *expected,
+    PyObject *arg);
 
 PyDoc_STRVAR(_curses_panel_panel_bottom__doc__,
 "bottom($self, /)\n"
diff --git a/py313/clinic/_cursesmodule.c.h b/py313/clinic/_cursesmodule.c.h
index 5fbe351..ef7d250 100644
--- a/py313/clinic/_cursesmodule.c.h
+++ b/py313/clinic/_cursesmodule.c.h
@@ -6,7 +6,45 @@ preserve
 #  include "pycore_gc.h"          // PyGC_Head
 #  include "pycore_runtime.h"     // _Py_ID()
 #endif
-#include "pycore_modsupport.h"    // _PyArg_CheckPositional()
+
+PyAPI_FUNC(int) _PyArg_CheckPositional(const char *, Py_ssize_t,
+                                       Py_ssize_t, Py_ssize_t);
+#define _Py_ANY_VARARGS(n) ((n) == PY_SSIZE_T_MAX)
+#define _PyArg_CheckPositional(funcname, nargs, min, max) \
+    ((!_Py_ANY_VARARGS(max) && (min) <= (nargs) && (nargs) <= (max)) \
+     || _PyArg_CheckPositional((funcname), (nargs), (min), (max)))
+
+// Export for '_heapq' shared extension
+PyAPI_FUNC(void) _PyArg_BadArgument(
+    const char *fname,
+    const char *displayname,
+    const char *expected,
+    PyObject *arg);
+
+// Export for '_curses' shared extension
+PyAPI_FUNC(int) _PyArg_ParseStack(
+    PyObject *const *args,
+    Py_ssize_t nargs,
+    const char *format,
+    ...);
+
+// Export for 'math' shared extension
+PyAPI_FUNC(PyObject * const *) _PyArg_UnpackKeywords(
+    PyObject *const *args,
+    Py_ssize_t nargs,
+    PyObject *kwargs,
+    PyObject *kwnames,
+    struct _PyArg_Parser *parser,
+    int minpos,
+    int maxpos,
+    int minkw,
+    PyObject **buf);
+#define _PyArg_UnpackKeywords(args, nargs, kwargs, kwnames, parser, minpos, maxpos, minkw, buf) \
+    (((minkw) == 0 && (kwargs) == NULL && (kwnames) == NULL && \
+      (minpos) <= (nargs) && (nargs) <= (maxpos) && (args) != NULL) ? (args) : \
+     _PyArg_UnpackKeywords((args), (nargs), (kwargs), (kwnames), (parser), \
+                           (minpos), (maxpos), (minkw), (buf)))
+
 
 PyDoc_STRVAR(_curses_window_addch__doc__,
 "addch([y, x,] ch, [attr=_curses.A_NORMAL])\n"