This is being emitted with [GCC 10.2.1](https://packages.debian.org/bullseye/g++-arm-linux-gnueabihf), in some CI jobs: i.e https://github.com/bitcoin/bitcoin/pull/25972/checks?check_run_id=12423693655, or https://github.com/bitcoin/bitcoin/pull/25972/checks?check_run_id=12423693651 (where we actually turn on all our warning flags with depends builds).
```bash
In file included from test/miniscript_tests.cpp:19:
./script/miniscript.h:1197:71: error: comparison of integers of different signs: 'typename iterator_traits<int *>::difference_type' (aka 'int') and 'const uint32_t' (aka 'const unsigned int') [-Werror,-Wsign-compare]
                    return std::count(subs.begin(), subs.end(), true) >= node.k;
                           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~
test/miniscript_tests.cpp:346:34: note: in instantiation of function template specialization 'miniscript::Node<CPubKey>::IsSatisfiable<(lambda at test/miniscript_tests.cpp:346:48)>' requested here
        bool satisfiable = node->IsSatisfiable([](const Node&) { return true; });
                                 ^
1 error generated.
```

cc @darosior 
constructed.pop_back();
            auto mid = std::move(constructed.back());
            constructed.pop_back();
            constructed.back() = MakeNodeRef<Key>(internal::NoDupCheck{}, Fragment::ANDOR, Vector(std::move(constructed.back()), std::move(mid), std::move(right)));
            break;
        }
        case ParseContext::THRESH: {
            if (in.size() < 1) return {};
            if (in[0] == ',') {
                in = in.subspan(1);
                to_parse.emplace_back(ParseContext::THRESH, n+1, k);
                to_parse.emplace_back(ParseContext::WRAPPED_EXPR, -1, -1);
                script_size += 2;
            } else if (in[0] == ')') {
                if (k > n) return {};
                in = in.subspan(1);
                
                std::vector<NodeRef<Key>> subs;
                for (int i = 0; i < n; ++i) {
                    subs.push_back(std::move(constructed.back()));
                    constructed.pop_back();
                }
                std::reverse(subs.begin(), subs.end());
                constructed.push_back(MakeNodeRef<Key>(internal::NoDupCheck{}, Fragment::THRESH, std::move(subs), k));
            } else {
                return {};
            }
            break;
        }
        case ParseContext::COMMA: {