diff -up swig-1.3.35/Source/Preprocessor/cpp.c.arch swig-1.3.35/Source/Preprocessor/cpp.c
--- swig-1.3.35/Source/Preprocessor/cpp.c.arch	2008-05-16 10:10:38.000000000 +0200
+++ swig-1.3.35/Source/Preprocessor/cpp.c	2008-05-16 10:15:40.000000000 +0200
@@ -187,6 +187,14 @@ void Preprocessor_init(void) {
 
   id_scan = NewScanner();;
 
+#ifdef __x86_64__
+  Preprocessor_define("__x86_64__", 0);
+#elif defined(__powerpc64__)
+  Preprocessor_define("__powerpc64__", 0);
+#else
+  Preprocessor_define("__i386__", 0);
+#endif
+
 }
 
 void Preprocessor_delete(void) {