diff -up swig-1.3.33/Source/Preprocessor/cpp.c.arch swig-1.3.33/Source/Preprocessor/cpp.c
--- swig-1.3.33/Source/Preprocessor/cpp.c.arch	2007-10-08 14:02:56.000000000 +0200
+++ swig-1.3.33/Source/Preprocessor/cpp.c	2007-11-29 10:13:15.000000000 +0100
@@ -186,6 +186,11 @@ void Preprocessor_init(void) {
   included_files = NewHash();
 
   id_scan = NewScanner();;
+#ifdef __x86_64__
+  Preprocessor_define("__x86_64__", 0);
+#elif defined __i386__
+  Preprocessor_define("__i386__", 0);
+#endif
 
 }