diff -up M2Crypto-0.30.1/SWIG/_m2crypto.i.gcc_macros M2Crypto-0.30.1/SWIG/_m2crypto.i
--- M2Crypto-0.30.1/SWIG/_m2crypto.i.gcc_macros	2018-02-24 14:54:59.000000000 +0100
+++ M2Crypto-0.30.1/SWIG/_m2crypto.i	2018-05-19 06:07:31.032986837 +0200
@@ -7,6 +7,7 @@
  * Copyright (c) 2009-2010 Heikki Toivonen. All rights reserved.
  *
  */
+%import "gcc_macros.h"
 
 %module(threads=1) m2crypto
 /* We really don't need threadblock (PyGILState_Ensure() etc.) anywhere.
@@ -15,11 +16,6 @@
 %nothreadblock;
 %nothreadallow;
 
-#if SWIG_VERSION >= 0x030000
-#define __WCHAR_MAX__ __WCHAR_MAX
-#define __WCHAR_MIN__ __WCHAR_MIN
-#endif
-
 %{
 #ifdef _WIN32
 #define _WINSOCKAPI_