Fix the declaration type of `lily_gc_stopper`.
/* When destroying a value with a gc tag, set the tag to this to prevent destroy
from reentering it. The values are useless, but cannot be 0 or this will be
optimized as a NULL pointer. */
-const lily_gc_entry lily_gc_stopper =
+const lily_gc_entry *lily_gc_stopper =
+&(lily_gc_entry)
{
1,
1,
