#4499: silence compiler warning on AIX.

Patch from ActiveState.
diff --git a/Include/token.h b/Include/token.h
index 772a85e..9c19f5c 100644
--- a/Include/token.h
+++ b/Include/token.h
@@ -7,6 +7,8 @@
 extern "C" {
 #endif
 
+#undef TILDE   /* Prevent clash of our definition with system macro. Ex AIX, ioctl.h */
+
 #define ENDMARKER	0
 #define NAME		1
 #define NUMBER		2