diff --git a/PC/bdist_wininst/install.c b/PC/bdist_wininst/install.c
--- a/PC/bdist_wininst/install.c
+++ b/PC/bdist_wininst/install.c
@@ -671,35 +671,35 @@ static HINSTANCE LoadPythonDll(char *fna
 }
 
 static int prepare_script_environment(HINSTANCE hPython)
 {
     PyObject *mod;
     DECLPROC(hPython, PyObject *, PyImport_ImportModule, (char *));
     DECLPROC(hPython, int, PyObject_SetAttrString, (PyObject *, char *, PyObject *));
     DECLPROC(hPython, PyObject *, PyObject_GetAttrString, (PyObject *, char *));
-    DECLPROC(hPython, PyObject *, PyCFunction_New, (PyMethodDef *, PyObject *));
+    DECLPROC(hPython, PyObject *, PyCFunction_NewEx, (PyMethodDef *, PyObject *, PyObject *));
     DECLPROC(hPython, PyObject *, Py_BuildValue, (char *, ...));
     DECLPROC(hPython, int, PyArg_ParseTuple, (PyObject *, char *, ...));
     DECLPROC(hPython, PyObject *, PyErr_Format, (PyObject *, char *));
     DECLPROC(hPython, PyObject *, PyLong_FromVoidPtr, (void *));
     if (!PyImport_ImportModule || !PyObject_GetAttrString ||
-        !PyObject_SetAttrString || !PyCFunction_New)
+        !PyObject_SetAttrString || !PyCFunction_NewEx)
         return 1;
     if (!Py_BuildValue || !PyArg_ParseTuple || !PyErr_Format)
         return 1;
 
     mod = PyImport_ImportModule("builtins");
     if (mod) {
         int i;
         g_PyExc_ValueError = PyObject_GetAttrString(mod, "ValueError");
         g_PyExc_OSError = PyObject_GetAttrString(mod, "OSError");
         for (i = 0; i < DIM(meth); ++i) {
             PyObject_SetAttrString(mod, meth[i].ml_name,
-                                   PyCFunction_New(&meth[i], NULL));
+                                   PyCFunction_NewEx(&meth[i], NULL, NULL));
         }
     }
     g_Py_BuildValue = Py_BuildValue;
     g_PyArg_ParseTuple = PyArg_ParseTuple;
     g_PyErr_Format = PyErr_Format;
     g_PyLong_FromVoidPtr = PyLong_FromVoidPtr;
 
     return 0;
@@ -720,29 +720,29 @@ do_run_installscript(HINSTANCE hPython, 
 {
     int fh, result, i;
     static wchar_t *wargv[256];
     DECLPROC(hPython, void, Py_Initialize, (void));
     DECLPROC(hPython, int, PySys_SetArgv, (int, wchar_t **));
     DECLPROC(hPython, int, PyRun_SimpleString, (char *));
     DECLPROC(hPython, void, Py_Finalize, (void));
     DECLPROC(hPython, PyObject *, Py_BuildValue, (char *, ...));
-    DECLPROC(hPython, PyObject *, PyCFunction_New,
-             (PyMethodDef *, PyObject *));
+    DECLPROC(hPython, PyObject *, PyCFunction_NewEx,
+             (PyMethodDef *, PyObject *, PyObject *));
     DECLPROC(hPython, int, PyArg_ParseTuple, (PyObject *, char *, ...));
     DECLPROC(hPython, PyObject *, PyErr_Format, (PyObject *, char *));
 
     if (!Py_Initialize || !PySys_SetArgv
         || !PyRun_SimpleString || !Py_Finalize)
         return 1;
 
     if (!Py_BuildValue || !PyArg_ParseTuple || !PyErr_Format)
         return 1;
 
-    if (!PyCFunction_New || !PyArg_ParseTuple || !PyErr_Format)
+    if (!PyCFunction_NewEx || !PyArg_ParseTuple || !PyErr_Format)
         return 1;
 
     if (pathname == NULL || pathname[0] == '\0')
         return 2;
 
     fh = open(pathname, _O_RDONLY | O_NOINHERIT);
     if (-1 == fh) {
         fprintf(stderr, "Could not open postinstall-script %s\n",