Have this warning while building current master (0bd4929cd00e91bf4137f43b097cd62f72f503e4) on one test machine.
```
wallet/rpcwallet.cpp: In function 'rescanblockchain()::<lambda(const RPCHelpMan&, const JSONRPCRequest&)>':
wallet/rpcwallet.cpp:3596:19: warning: '*((void*)& stop_height +4)' may be used uninitialized in this function [-Wmaybe-uninitialized]
 3596 |     Optional<int> stop_height;
      |                   ^~~~~~~~~~~
```
```
$ gcc --version
gcc (Gentoo 9.2.0-r2 p3) 9.2.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ uname -a
Linux red-box 4.19.72-gentoo #2 SMP Sun Sep 22 03:00:01 EEST 2019 x86_64 Intel(R) Pentium(R) CPU N3710 @ 1.60GHz GenuineIntel GNU/Linux
```
{
    return RPCHelpMan{"addmultisigaddress",
                "\nAdd an nrequired-to-sign multisignature address to the wallet. Requires a new wallet backup.\n"
                "Each key is a Bitcoin address or hex-encoded public key.\n"
                "This functionality is only intended for use with non-watchonly addresses.\n"
                "See `importaddress` for watchonly p2sh address support.\n"
                "If 'label' is specified, assign address to that label.\n",
                {
                    {"nrequired", RPCArg::Type::NUM, RPCArg::Optional::NO, "The number of required signatures out of the n keys or addresses."},
                    {"keys", RPCArg::Type::ARR, RPCArg::Optional::NO, "The bitcoin addresses or hex-encoded public keys",
                        {
                            {"key", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "bitcoin address or hex-encoded public key"},
                        },
                        },
                    {"label", RPCArg::Type::STR, RPCArg::Optional::OMITTED_NAMED_ARG, "A label to assign the addresses to."},
                    {"address_type", RPCArg::Type::STR,  "set by -addresstype", "The address type to use. Options are \"legacy\", \"p2sh-segwit\", and \"bech32\"."},
                },
                RPCResult{
                    RPCResult::Type::OBJ, "", "",