Index: python3.5-3.5.3/Modules/fcntlmodule.c
===================================================================
--- python3.5-3.5.3.orig/Modules/fcntlmodule.c	2017-01-17 08:57:53.000000000 +0100
+++ python3.5-3.5.3/Modules/fcntlmodule.c	2017-06-14 15:13:47.188342592 +0200
@@ -161,7 +161,7 @@
        in their unsigned long ioctl codes this will break and need
        special casing based on the platform being built on.
      */
-    int arg = 0;
+    unsigned long arg = 0;
     int ret;
     Py_buffer pstr;
     char *str;
@@ -247,7 +247,7 @@
 
         PyErr_Clear();
         if (!PyArg_Parse(ob_arg,
-             "i;ioctl requires a file or file descriptor,"
+             "k;ioctl requires a file or file descriptor,"
              " an integer and optionally an integer or buffer argument",
              &arg)) {
           return NULL;