Building 4.3.2 on macOS 10.12 fails: error: no member named 'toggleVisibility' in 'MainWindow'

[i0ntempest]

moc_mainwindow.cpp:433:22: error: no member named 'toggleVisibility' in 'MainWindow'
        case 70: _t->toggleVisibility((*reinterpret_cast< const QSystemTrayIcon::ActivationReason(*)>(_a[1]))); break;
                 ~~  ^
compiling moc_peerlistwidget.cpp
moc_mainwindow.cpp:433:65: error: use of undeclared identifier 'QSystemTrayIcon'
        case 70: _t->toggleVisibility((*reinterpret_cast< const QSystemTrayIcon::ActivationReason(*)>(_a[1]))); break;
                                                                ^
moc_mainwindow.cpp:433:40: warning: ISO C++ does not allow indirection on operand of type 'void *' [-Wvoid-ptr-dereference]
        case 70: _t->toggleVisibility((*reinterpret_cast< const QSystemTrayIcon::ActivationReason(*)>(_a[1]))); break;
                                       ^                                                              ~~~~~
moc_mainwindow.cpp:434:22: error: no member named 'toggleVisibility' in 'MainWindow'
        case 71: _t->toggleVisibility(); break;
                 ~~  ^
moc_mainwindow.cpp:435:22: error: no member named 'createSystrayDelayed' in 'MainWindow'
        case 72: _t->createSystrayDelayed(); break;
                 ~~  ^
moc_mainwindow.cpp:436:22: error: no member named 'updateTrayIconMenu' in 'MainWindow'; did you mean 'trayIconMenu'?
        case 73: _t->updateTrayIconMenu(); break;
                     ^~~~~~~~~~~~~~~~~~
                     trayIconMenu
./gui/mainwindow.h:85:12: note: 'trayIconMenu' declared here
    QMenu *trayIconMenu();
           ^
compiling moc_peersadditiondialog.cpp
1 warning and 5 errors generated.

Compiling with CMake would give a different error:

/Users/Admin/Downloads/qbittorrent-qBittorrent-e331f48/src/base/utils/misc.cpp:474:31: warning: direct list initialization of a variable with a deduced
      type will change meaning in a future version of Clang; insert an '=' to avoid a change in behavior [-Wfuture-compat]
    static const auto version {QString::fromLatin1(lt::version())};
                              ^
                              =
/Users/Admin/Downloads/qbittorrent-qBittorrent-e331f48/src/base/utils/misc.cpp:475:12: error: no viable conversion from
      'const std::initializer_list<QString>' to 'QString'
    return version;
           ^~~~~~~
/Users/Admin/Downloads/qbittorrent-qBittorrent-e331f48/src/base/utils/misc.cpp:481:31: warning: direct list initialization of a variable with a deduced
      type will change meaning in a future version of Clang; insert an '=' to avoid a change in behavior [-Wfuture-compat]
    static const auto version {QString::fromLatin1(OpenSSL_version(OPENSSL_VERSION))};
                              ^
                              =
/Users/Admin/Downloads/qbittorrent-qBittorrent-e331f48/src/base/utils/misc.cpp:485:20: error: no member named 'splitRef' in
      'std::initializer_list<QString>'
    return version.splitRef(' ', QString::SkipEmptyParts)[1].toString();
           ~~~~~~~ ^
/Users/Admin/Downloads/qbittorrent-qBittorrent-e331f48/src/base/utils/misc.cpp:491:31: warning: direct list initialization of a variable with a deduced
      type will change meaning in a future version of Clang; insert an '=' to avoid a change in behavior [-Wfuture-compat]
    static const auto version {QString::fromLatin1(zlibVersion())};
                              ^
                              =
/Users/Admin/Downloads/qbittorrent-qBittorrent-e331f48/src/base/utils/misc.cpp:492:12: error: no viable conversion from
      'const std::initializer_list<QString>' to 'QString'
    return version;
           ^~~~~~~

I'm the maintainer of qBittorrent on macports and I'd like to make qBit usable on as many OS versions as possible. I understand this is a legacy support question that probably no one want to put much efforts in, but still I want to see if anything can be done. For a brief peroid of time 4.3.2 could be built on down to OS X 10.10 (with Qt 5.9) on our buildbots. I'm not sure what changed that causes this error now. Full build log is here: https://build.macports.org/builders/ports-10.12_x86_64-builder/builds/192281/steps/install-port/logs/stdio

Help appreciated!!