Index: compiler.h
===================================================================
--- compiler.h	(revision 4471)
+++ compiler.h	(working copy)
@@ -185,7 +185,7 @@
 #endif
 
 #ifdef __GNUC__
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
+#if defined(__GXX_EXPERIMENTAL_CXX0X__) || defined(__LP64__)
 #ifdef __LONG_LONG_MAX__
     __extension__ typedef long long int rcpp_long_long_type;
     __extension__ typedef unsigned long long int rcpp_ulong_long_type;
