From what I can tell `CClientUIInterface::[signal_name]_disconnect` is a no-op.

In other words calling it does *not* disconnect the slot:

For example `uiInterface.NotifyBlockTip_disconnect(BlockNotifyGenesisWait);` in `AppInitMain(...)` does not disconnect `BlockNotifyGenesisWait` as one would expect. The result being that `BlockNotifyGenesisWait` is invoked for every new block :-)

Running `bitcoind` with some debug printing added shows the issue:

```
[signals] CClientUIInterface::ThreadSafeMessageBox_connect(...) entered with 0 connected slots.
[signals] CClientUIInterface::ThreadSafeMessageBox_connect(...) exited with 1 connected slots.
[signals] CClientUIInterface::ThreadSafeQuestion_connect(...) entered with 0 connected slots.
[signals] CClientUIInterface::ThreadSafeQuestion_connect(...) exited with 1 connected slots.
[signals] CClientUIInterface::InitMessage_connect(...) entered with 0 connected slots.
[signals] CClientUIInterface::InitMessage_connect(...) exited with 1 connected slots.
[signals] CClientUIInterface::InitMessage_connect(...) entered with 1 connected slots.
[signals] CClientUIInterface::InitMessage_connect(...) exited with 2 connected slots.
[signals] Calling uiInterface.NotifyBlockTip_connect(&RPCNotifyBlockChange) in OnRPCStarted()
[signals] CClientUIInterface::NotifyBlockTip_connect(...) entered with 0 connected slots.
[signals] CClientUIInterface::NotifyBlockTip_connect(...) exited with 1 connected slots.
[signals] Calling uiInterface.NotifyBlockTip_connect(BlockNotifyGenesisWait) in AppInitMain(...)
[signals] CClientUIInterface::NotifyBlockTip_connect(...) entered with 1 connected slots.
[signals] CClientUIInterface::NotifyBlockTip_connect(...) exited with 2 connected slots.
[signals] RPCNotifyBlockChange(...) was invoked.
[signals] BlockNotifyGenesisWait(...) was invoked.
[signals] Calling uiInterface.NotifyBlockTip_disconnect(BlockNotifyGenesisWait) in AppInitMain(...)
[signals] CClientUIInterface::NotifyBlockTip_disconnect(...) entered with 2 connected slots.
[signals] CClientUIInterface::NotifyBlockTip_disconnect(...) exited with 2 connected slots.
[signals] RPCNotifyBlockChange(...) was invoked.
[signals] BlockNotifyGenesisWait(...) was invoked.
[signals] RPCNotifyBlockChange(...) was invoked.
[signals] BlockNotifyGenesisWait(...) was invoked.
[signals] RPCNotifyBlockChange(...) was invoked.
[signals] BlockNotifyGenesisWait(...) was invoked.
... and so on ...
```

Note how `BlockNotifyGenesisWait(...)` is called also after `uiInterface.NotifyBlockTip_disconnect(BlockNotifyGenesisWait)`.

I think the problem is that the `disconnect(...)` member function of `boost::signals2::signal` expects a function pointer to be passed in (the same that was passed to `.connect(...)`), but we're doing:

```
void CClientUIInterface::signal_name##_disconnect(std::function<signal_name##Sig> fn)
{
    return g_ui_signals.signal_name.disconnect(&fn);
}
```
fs::path config_file_path = GetConfigFile(gArgs.GetArg("-conf", BITCOIN_CONF_FILENAME));
    if (fs::exists(config_file_path)) {
        LogPrintf("Config file: %s\n", config_file_path.string());
    } else if (gArgs.IsArgSet("-conf")) {
        
        InitWarning(strprintf(_("The specified config file %s does not exist\n"), config_file_path.string()));
    } else {
        
        LogPrintf("Config file: %s (not found, skipping)\n", config_file_path.string());
    }
    LogPrintf("Using at most %i automatic connections (%i file descriptors available)\n", nMaxConnections, nFD);
    
    if (gArgs.IsArgSet("-datadir") && !fs::path(gArgs.GetArg("-datadir", "")).is_absolute()) {
        LogPrintf("Warning: relative datadir option '%s' specified, which will be interpreted relative to the " 
                  "current working directory '%s'. This is fragile, because if bitcoin is started in the future "
                  "from a different location, it will be unable to locate the current data files. There could "
                  "also be data loss if bitcoin is started while in a temporary directory.\n",
            gArgs.GetArg("-datadir", ""), fs::current_path().string());
    }
    InitSignatureCache();
    InitScriptExecutionCache();
    LogPrintf("Using %u threads for script verification\n", nScriptCheckThreads);
    if (nScriptCheckThreads) {
        for (int i=0; i<nScriptCheckThreads-1; i++)
            threadGroup.create_thread(&ThreadScriptCheck);
    }
    
    CScheduler::Function serviceLoop = std::bind(&CScheduler::serviceQueue, &scheduler);
    threadGroup.create_thread(std::bind(&TraceThread<CScheduler::Function>, "scheduler", serviceLoop));