Fix a syntax error for platform010
Fix a syntax error for platform010

Summary:
This diff fixes a syntax error for platform010. The errors fixed look like one of the following:
```
buck-out/v2/gen/fbcode/6dbc4bb1b9a32829/manifold/client/__client_request_controller__/headers/manifold/client/ClientRequestController.h:106:11: error: '~ClientRequestController' overrides a destructor but is not marked 'override' [-Werror,-Wsuggest-destructor-override]
  virtual ~ClientRequestController();
          ^

buck-out/v2/gen/fbcode/6dbc4bb1b9a32829/manifold/util/__lrucache__/headers/manifold/util/MfLruCache.h:187:38: error: use of function '__builtin_alloca' is discouraged; there is no way to check for failure but failure may still occur, resulting in a possibly exploitable security vulnerability [-Werror,-Walloca]
    uint32_t *indices = (uint32_t *) alloca(sizeof(uint32_t) * n);
                                     ^
```

Reviewed By: alyssaverkade

Differential Revision: D35689204

fbshipit-source-id: 3d26edf5433f9498ab35ba6f343b7bb3728d4abe

facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst