util: uid_t, gid_t, and pid_t must be 32bit

We already have assert_cc(sizeof(uid_t) == sizeof(uint32_t)) or friends
at various places.

src/core/dbus-manager.c

@@ -1663,7 +1663,7 @@ static int method_lookup_dynamic_user_by_uid(sd_bus_message *message, void *user
         assert(message);
         assert(m);
 
-        assert_cc(sizeof(uid) == sizeof(uint32_t));
+        assert_cc(sizeof(uid_t) == sizeof(uint32_t));
         r = sd_bus_message_read_basic(message, 'u', &uid);
         if (r < 0)
                 return r;