File libprelude-fix_64bit_portability_issues.patch of Package libprelude

--- ./src/idmef-class.c	2018-12-23 21:59:17.870000000 +0100
+++ ./src/idmef-class.c	2019-03-01 22:56:55.089210704 +0100
@@ -161,7 +161,7 @@
 
         ret = is_child_valid(class, child);
         if ( ret < 0 )
-                return ret;
+                return NULL;
 
         return object_data[class].children_list[child].attributes;
 }