Fix warnings

This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.

third_party/quickjs/map.c

@@ -318,6 +318,7 @@ void reset_weak_ref(JSRuntime *rt, JSObject *p)
 {
     JSMapRecord *mr, *mr_next;
     JSMapState *s;
+    (void)s;
     /* first pass to remove the records from the WeakMap/WeakSet
        lists */
     for(mr = p->first_weak_ref; mr != NULL; mr = mr->next_weak_ref) {