add clone2 prototype to shutup warnings

test/unistd/clone_cruft.h

@@ -6,6 +6,8 @@
 
 #if defined __ia64__
 
+extern int __clone2 (int (*__fn) (void *__arg), void *__child_stack_base,
+                     size_t __child_stack_size, int __flags, void *__arg, ...);
 # define do_clone(fn, stack, flags, arg) \
 	__clone2(fn, stack, crappy_sizeof(stack), flags, arg, NULL, NULL, NULL)