Accept bytes as parameter to foreign functions without prototype.

These are passed as byte strings (unicode strings are passed as wide
character strings).

Lib/ctypes/test/test_slicing.py

@@ -37,7 +37,7 @@ class SlicesTestCase(unittest.TestCase):
     from ctypes.test import is_resource_enabled
     if is_resource_enabled("struni-crash"):
         def test_char_ptr(self):
-            s = "abcdefghijklmnopqrstuvwxyz"
+            s = b"abcdefghijklmnopqrstuvwxyz"
 
             dll = CDLL(_ctypes_test.__file__)
             dll.my_strdup.restype = POINTER(c_char)
@@ -57,7 +57,7 @@ class SlicesTestCase(unittest.TestCase):
 
         def test_char_ptr_with_free(self):
             dll = CDLL(_ctypes_test.__file__)
-            s = "abcdefghijklmnopqrstuvwxyz"
+            s = b"abcdefghijklmnopqrstuvwxyz"
 
             class allocated_c_char_p(c_char_p):
                 pass

Modules/_ctypes/callproc.c

@@ -512,6 +512,7 @@ static int ConvParam(PyObject *obj, Py_ssize_t index, struct argument *pa)
 		return 0;
 	}
 
+	/* XXX struni remove later */
 	if (PyString_Check(obj)) {
 		pa->ffi_type = &ffi_type_pointer;
 		pa->value.p = PyString_AS_STRING(obj);
@@ -520,6 +521,14 @@ static int ConvParam(PyObject *obj, Py_ssize_t index, struct argument *pa)
 		return 0;
 	}
 
+	if (PyBytes_Check(obj)) {
+		pa->ffi_type = &ffi_type_pointer;
+		pa->value.p = PyBytes_AsString(obj);
+		Py_INCREF(obj);
+		pa->keep = obj;
+		return 0;
+	}
+
 #ifdef CTYPES_UNICODE
 	if (PyUnicode_Check(obj)) {
 #ifdef HAVE_USABLE_WCHAR_T