-static void * (*old_malloc_hook) ();
-static void * (*old_realloc_hook) ();
-static void (*old_free_hook) ();
+static void * (*old_malloc_hook) P_ ((size_t, const void *));
+static void * (*old_realloc_hook) P_ ((void *, size_t, const void*));
+static void (*old_free_hook) P_ ((void*, const void*));