Fix output of return arguments in nested calls on x86_64
diff --git a/common.h b/common.h
index 20f1a96..753d3dc 100644
--- a/common.h
+++ b/common.h
@@ -149,6 +149,7 @@
 	int is_syscall;
 	void * return_addr;
 	struct timeval time_spent;
+	void * arch_ptr;
 };
 
 #define MAX_CALLDEPTH 64