compilation fails on ambiguous conversion to bool

In file included from /Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediaassetwriter.mm:41:
In file included from /Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediarecordercontrol_ios.h:43:
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediaassetwriter.h:63:42: warning: declaration of instance variables in
      the interface is deprecated [-Wobjc-interface-ivars]
    QT_PREPEND_NAMESPACE(AVFAtomicInt64) m_durationInMs;
                                         ^
cd lconvert/ && ( test -e Makefile || /Users/foxi/QtFoxi/qt-5.13.2/qtbase/bin/qmake -o Makefile /Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qttools/src/linguist/lconvert/lconvert.pro ) && /Applications/Xcode.app/Contents/Developer/usr/bin/make -f Makefile 
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediaassetwriter.mm:369:29: warning: null passed to a callee that requires
      a non-null argument [-Wnonnull]
                [vfDelegate captureOutput:nil didOutputSampleBuffer:sampleBuffer fromConnection:nil];
                            ^             ~~~
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediaassetwriter.mm:369:29: warning: null passed to a callee that requires
      a non-null argument [-Wnonnull]
                [vfDelegate captureOutput:nil didOutputSampleBuffer:sampleBuffer fromConnection:nil];
                            ^                                                                   ~~~
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediaassetwriter.mm:416:9: error: conversion from
      '::AVFScopedPointer<AVCaptureAudioDataOutput>' to 'bool' is ambiguous
    if (m_audioOutput && [captureSession canAddOutput:m_audioOutput]) {
        ^~~~~~~~~~~~~
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfcamerautility.h:100:5: note: candidate function
    operator T*() const
    ^
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtbase/include/QtCore/../../src/corelib/tools/qscopedpointer.h:132:5: note: candidate function
    operator RestrictedBool() const Q_DECL_NOTHROW
    ^
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediaassetwriter.mm:434:5: error: conversion from
      '::AVFScopedPointer<AVAssetWriter>' to 'bool' is ambiguous
    Q_ASSERT(m_assetWriter);
    ^~~~~~~~~~~~~~~~~~~~~~~
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtbase/include/QtCore/../../src/corelib/global/qglobal.h:788:55: note: expanded from macro 'Q_ASSERT'
#    define Q_ASSERT(cond) static_cast<void>(false && (cond))
                                                      ^~~~~~
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfcamerautility.h:100:5: note: candidate function
    operator T*() const
    ^
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtbase/include/QtCore/../../src/corelib/tools/qscopedpointer.h:132:5: note: candidate function
    operator RestrictedBool() const Q_DECL_NOTHROW
    ^
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediaassetwriter.mm:454:9: error: conversion from
      '::AVFScopedPointer<AVCaptureAudioDataOutput>' to 'bool' is ambiguous
    if (m_audioOutput) {
        ^~~~~~~~~~~~~
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfcamerautility.h:100:5: note: candidate function
    operator T*() const
    ^
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtbase/include/QtCore/../../src/corelib/tools/qscopedpointer.h:132:5: note: candidate function
    operator RestrictedBool() const Q_DECL_NOTHROW
    ^
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfmediaassetwriter.mm:482:9: error: conversion from
      '::AVFScopedPointer<AVCaptureAudioDataOutput>' to 'bool' is ambiguous
    if (m_audioOutput) {
        ^~~~~~~~~~~~~
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtmultimedia/src/plugins/avfoundation/camera/avfcamerautility.h:100:5: note: candidate function
    operator T*() const
    ^
/Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qtbase/include/QtCore/../../src/corelib/tools/qscopedpointer.h:132:5: note: candidate function
    operator RestrictedBool() const Q_DECL_NOTHROW
    ^
make[4]: Nothing to be done for `first'.
cd lprodump/ && ( test -e Makefile || /Users/foxi/QtFoxi/qt-5.13.2/qtbase/bin/qmake -o Makefile /Users/foxi/QtFoxi/qt-everywhere-src-5.13.2/qttools/src/linguist/lprodump/lprodump.pro ) && /Applications/Xcode.app/Contents/Developer/usr/bin/make -f Makefile 
3 warnings and 4 errors generated.
make[5]: *** [.obj/avfmediaassetwriter.o] Error 1
make[4]: *** [sub-camera-make_first] Error 2
make[3]: *** [sub-avfoundation-make_first] Error 2
make[2]: *** [sub-plugins-make_first] Error 2
make[1]: *** [sub-src-make_first] Error 2
make: *** [module-qtmultimedia-make_first] Error 2
make: *** Waiting for unfinished jobs....