WIN64: 'cast between incompatible function types ... [-Werror=cast-function-type]' errors for builds using mingw-w64 8.1.0

g++ -c -fno-keep-inline-dllexport -O2 -std=c++1y -ffunction-sections -fdata-sections -fno-exceptions -Wall -W -Wextra -Wvla -Wdate-time -Wshift-overflow=2 -Wduplicated-cond -Wno-stringop-overflow -Werror -Wno-error=cpp -Wno-error=deprecated-declarations -Wno-error=strict-overflow -Wno-error=implicit-fallthrough -DUNICODE -D_UNICODE -DWIN32 -DWINVER=0x0601 -D_WIN32_WINNT=0x0601 -DQT_VERSION_STR="\"5.12.0\"" -DQT_VERSION_MAJOR=5 -DQT_VERSION_MINOR=12 -DQT_VERSION_PATCH=0 -DQT_BOOTSTRAPPED -DQT_NO_CAST_TO_ASCII -DQT_NO_FOREACH -DQT_NO_CAST_FROM_ASCII -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_BOOTSTRAP_LIB -DQT_BUILDING_QT -D_CRT_SECURE_NO_WARNINGS -D_USE_MATH_DEFINES -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x040800 -DQT_NO_EXCEPTIONS -DQT_NO_DEBUG -DQT_FORCE_ASSERTS -I. -I..\..\..\include -I..\..\..\include\QtCore -I..\..\..\include\QtCore\5.12.0 -I..\..\..\include\QtCore\5.12.0\QtCore -I..\..\..\include\QtXml -I..\..\..\include\QtXml\5.12.0 -I..\..\..\include\QtXml\5.12.0\QtXml -Itmp -I..\..\..\mkspecs\win32-g++  -o .obj\release\qoperatingsystemversion_win.o ..\..\corelib\global\qoperatingsystemversion_win.cpp
..\..\corelib\global\qoperatingsystemversion_win.cpp: In function 'OSVERSIONINFOEX determineWinOsVersion()':
..\..\corelib\global\qoperatingsystemversion_win.cpp:100:48: error: cast between incompatible function types from 'FARPROC' {aka 'long long int (*)()'} to 'RtlGetVersionFunction' {aka 'long int (*)(_OSVERSIONINFOW*)'} [-Werror=cast-function-type]
         GetProcAddressA(ntdll, "RtlGetVersion"));
                                                ^
cc1plus.exe: all warnings being treated as errors
mingw32-make[1]: Leaving directory 'c:/libQT-5.12-dev/build/qtbase'
mingw32-make: *** [Makefile:81: module-qtbase-make_first] Error 2

mingw32-make[3]: Entering directory 'c:/libQT-5.12-dev/build/qtbase/src/network'
mingw32-make -f Makefile.Release
mingw32-make[4]: Entering directory 'c:/libQT-5.12-dev/build/qtbase/src/network'
g++ -c -fno-keep-inline-dllexport -Wno-error=cast-function-type -DOPENSSL_API_COMPAT=0x10100000L -O2 -std=c++1y -fno-exceptions -Wall -W -Wextra -Wvla -Wdate-time -Wshift-overflow=2 -Wduplicated-cond -Wno-stringop-overflow -Werror -Wno-error=cpp -Wno-error=deprecated-declarations -Wno-error=strict-overflow -Wno-error=implicit-fallthrough -DUNICODE -D_UNICODE -DWIN32 -DWINVER=0x0601 -D_WIN32_WINNT=0x0601 -DQT_NO_USING_NAMESPACE -DQT_NO_FOREACH -DQT_USE_SYSTEM_PROXIES -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_NETWORK_LIB -DQT_BUILDING_QT -D_CRT_SECURE_NO_WARNINGS -D_USE_MATH_DEFINES -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x040800 -DQT_NO_EXCEPTIONS -DQT_NO_DEBUG -DQT_FORCE_ASSERTS -DQT_CORE_LIB -I. -Ikernel -I..\..\include -I..\..\include\QtNetwork -I..\..\include\QtNetwork\5.12.0 -I..\..\include\QtNetwork\5.12.0\QtNetwork -Itmp -I..\..\include\QtCore\5.12.0 -I..\..\include\QtCore\5.12.0\QtCore -I..\..\include\QtCore -I.moc\release -Ic:\libOPENSSL-1.1.1-dev\GCC64RH\include -I..\..\mkspecs\win32-g++  -o .obj\release\qnetworkaccessdebugpipebackend.o access\qnetworkaccessdebugpipebackend.cpp
In file included from ..\..\include/QtCore/qdatastream.h:1,
                 from access\qnetworkaccessdebugpipebackend.cpp:41:
..\..\include/QtCore/../../src/corelib/serialization/qdatastream.h:349:21: error: 'QDataStream& QDataStream::operator>>(quint32&)' redeclared without dllimport attribute after being referenced with dll linkage [-Werror]
 inline QDataStream &QDataStream::operator>>(quint32 &i)
                     ^~~~~~~~~~~
..\..\include/QtCore/../../src/corelib/serialization/qdatastream.h:361:21: error: 'QDataStream& QDataStream::operator<<(quint32)' redeclared without dllimport attribute after being referenced with dll linkage [-Werror]
 inline QDataStream &QDataStream::operator<<(quint32 i)
                     ^~~~~~~~~~~
cc1plus.exe: all warnings being treated as errors
mingw32-make: *** [Makefile:81: module-qtbase-make_first] Error 2

mingw32-make[4]: Entering directory 'c:/libQT-5.12-dev/build/qtbase/src/gui'
g++ -c -fno-keep-inline-dllexport -O3 -std=c++1y -fno-exceptions -Wall -W -Wextra -Wvla -Wdate-time -Wshift-overflow=2 -Wduplicated-cond -Wno-stringop-overflow -DUNICODE -D_UNICODE -DWIN32 -DWINVER=0x0601 -D_WIN32_WINNT=0x0601 -DQT_NO_USING_NAMESPACE -DQT_NO_FOREACH -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_GUI_LIB -DQT_BUILDING_QT -D_CRT_SECURE_NO_WARNINGS -D_USE_MATH_DEFINES -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x040800 -DQT_NO_EXCEPTIONS -DQT_NO_DEBUG -DQT_FORCE_ASSERTS -DQT_CORE_LIB -I. -I..\..\include -I..\..\include\QtGui -I..\..\include\QtANGLE -I..\..\include\QtGui\5.12.0 -I..\..\include\QtGui\5.12.0\QtGui -Itmp -I.tracegen\release -I..\..\include\QtCore\5.12.0 -I..\..\include\QtCore\5.12.0\QtCore -I..\..\include\QtCore -I.moc\release -I"C:\Program Files (x86)\VulkanSDK\include" -I..\3rdparty\libpng -I..\3rdparty\harfbuzz-ng\include -I..\..\mkspecs\win32-g++  -o .obj\release\qpnghandler.o image\qpnghandler.cpp
In file included from ..\..\include/QtCore/qdatastream.h:1,
                 from ..\..\include/QtGui/../../src/gui/painting/qregion.h:49,
                 from ..\..\include/QtGui/qregion.h:1,
                 from ..\..\include/QtGui/../../src/gui/painting/qmatrix.h:45,
                 from ..\..\include/QtGui/qmatrix.h:1,
                 from ..\..\include/QtGui/../../src/gui/painting/qtransform.h:43,
                 from ..\..\include/QtGui/qtransform.h:1,
                 from ..\..\include\QtGui/../../src/gui/image/qimage.h:48,
                 from ..\..\include\QtGui/qimage.h:1,
                 from image\qpnghandler.cpp:46:
..\..\include/QtCore/../../src/corelib/serialization/qdatastream.h:349:21: warning: 'QDataStream& QDataStream::operator>>(quint32&)' redeclared without dllimport attribute after being referenced with dll linkage
 inline QDataStream &QDataStream::operator>>(quint32 &i)
                     ^~~~~~~~~~~
..\..\include/QtCore/../../src/corelib/serialization/qdatastream.h:361:21: warning: 'QDataStream& QDataStream::operator<<(quint32)' redeclared without dllimport attribute after being referenced with dll linkage
 inline QDataStream &QDataStream::operator<<(quint32 i)
                     ^~~~~~~~~~~
mingw32-make: *** [Makefile:81: module-qtbase-make_first] Error 2