Fixed a crash in ctypes, when HAVE_USABLE_WCHAR_T is false.

Fixes issue #4867.

Misc/NEWS

@@ -88,6 +88,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #4867: Fixed a crash in ctypes when passing a string to a
+  function without defining argtypes.
+
 - Issue #4272: Add an optional argument to the GzipFile constructor to override
   the timestamp in the gzip stream. The default value remains the current time.
   The information can be used by e.g. gunzip when decompressing. Patch by

Modules/_ctypes/callproc.c

@@ -645,8 +645,8 @@ static int ConvParam(PyObject *obj, Py_ssize_t index, struct argument *pa)
 
 #ifdef CTYPES_UNICODE
 	if (PyUnicode_Check(obj)) {
-#ifdef HAVE_USABLE_WCHAR_T
 		pa->ffi_type = &ffi_type_pointer;
+#ifdef HAVE_USABLE_WCHAR_T
 		pa->value.p = PyUnicode_AS_UNICODE(obj);
 		Py_INCREF(obj);
 		pa->keep = obj;