--- pth.h.in	Thu Jun  8 10:54:02 2006
+++ pth.h.in	Thu Sep 17 09:06:18 2009
@@ -89,10 +89,12 @@
 
     /* check if the user requests a bigger FD_SETSIZE than we can handle */
 #if defined(FD_SETSIZE)
+#ifndef _LP64
 #if FD_SETSIZE > @PTH_FDSETSIZE@
 #error "FD_SETSIZE is larger than what GNU Pth can handle."
 #endif
 #endif
+#endif
 
 BEGIN_DECLARATION