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 
break;
            }
            
            if (in[0].first == OP_0NOTEQUAL) {
                ++in;
                to_parse.emplace_back(DecodeContext::ZERO_NOTEQUAL, -1, -1);
                to_parse.emplace_back(DecodeContext::SINGLE_BKV_EXPR, -1, -1);
                break;
            }
            
            if (last - in >= 3 && in[0].first == OP_EQUAL && (num = ParseScriptNumber(in[1]))) {
                if (*num < 1) return {};
                in += 2;
                to_parse.emplace_back(DecodeContext::THRESH_W, 0, *num);
                break;
            }
            
            if (in[0].first == OP_ENDIF) {
                ++in;
                to_parse.emplace_back(DecodeContext::ENDIF, -1, -1);
                to_parse.emplace_back(DecodeContext::BKV_EXPR, -1, -1);
                break;
            }
            /** In and_b and or_b nodes, we only look for SINGLE_BKV_EXPR, because
             * or_b(and_v(X,Y),Z) has script [X] [Y] [Z] OP_BOOLOR, the same as
             * and_v(X,or_b(Y,Z)). In this example, the former of these is invalid as
             * miniscript, while the latter is valid. So we leave the and_v "outside"
             * while decoding. */
            
            if (in[0].first == OP_BOOLAND) {