In atoi(), don't use isxdigit() to test whether the last character

converted was a "digit" -- use isalnum().  This test is there only to
guard against "+" or "-" being interpreted as a valid int literal.
Reported by Takahiro Nakayama.

Modules/stropmodule.c

@@ -818,7 +818,7 @@ strop_atoi(self, args)
 		x = (long) PyOS_strtoul(s, &end, base);
 	else
 		x = PyOS_strtol(s, &end, base);
-	if (end == s || !isxdigit(end[-1]))
+	if (end == s || !isalnum(end[-1]))
 		goto bad;
 	while (*end && isspace(Py_CHARMASK(*end)))
 		end++;