'undefined reference to `qt_static_plugin_QtQuick2WindowPlugin()' and 'unresolved external symbol' errors for QtVirtualKeyboard builds on Windows

cd examples\ && ( if not exist Makefile c:\libQT-5.10-dev\build\qtbase\bin\qmake.exe -o Makefile c:\libQT-5.10-dev\build\qtvirtualkeyboard\examples\examples.pro ) && mingw32-make -f Makefile
mingw32-make[1]: Entering directory 'c:/libQT-5.10-dev/build/qtvirtualkeyboard/examples'
cd virtualkeyboard\ && ( if not exist Makefile c:\libQT-5.10-dev\build\qtbase\bin\qmake.exe -o Makefile c:\libQT-5.10-dev\build\qtvirtualkeyboard\examples\virtualkeyboard\virtualkeyboard.pro ) && mingw32-make -f Makefile
mingw32-make[2]: Entering directory 'c:/libQT-5.10-dev/build/qtvirtualkeyboard/examples/virtualkeyboard'
cd basic\ && ( if not exist Makefile c:\libQT-5.10-dev\build\qtbase\bin\qmake.exe -o Makefile c:\libQT-5.10-dev\build\qtvirtualkeyboard\examples\virtualkeyboard\basic\basic.pro ) && mingw32-make -f Makefile
mingw32-make[3]: Entering directory 'c:/libQT-5.10-dev/build/qtvirtualkeyboard/examples/virtualkeyboard/basic'
mingw32-make -f Makefile.Release
mingw32-make[4]: Entering directory 'c:/libQT-5.10-dev/build/qtvirtualkeyboard/examples/virtualkeyboard/basic'
g++ -Wl,-s -static -Wl,-subsystem,windows -o release\basic.exe .obj/release/main.o .obj/release/basic_plugin_import.o .obj/release/basic_qml_plugin_import.o .obj/release/qrc_demo.o  -lmingw32 -Lc:\libQT-5.10-dev\build\qtbase\lib c:\libQT-5.10-dev\build\qtbase\lib\libqtmain.a -Lc:\libICU-59.1\GCC64RT\lib -Lc:\libQT-5.10-dev\build\qtvirtualkeyboard\plugins\platforminputcontexts c:\libQT-5.10-dev\build\qtvirtualkeyboard\plugins\platforminputcontexts\libqtvirtualkeyboardplugin.a -Lc:\libQT-5.10-dev\build\qtdeclarative\lib -Lc:\libQT-5.10-dev\build\qtbase\plugins\styles c:\libQT-5.10-dev\build\qtbase\plugins\styles\libqwindowsvistastyle.a -Lc:\libQT-5.10-dev\build\qtbase\plugins\platforms c:\libQT-5.10-dev\build\qtbase\plugins\platforms\libqwindows.a -lwinspool -lshlwapi -lrpcrt4 c:\libQT-5.10-dev\build\qtbase\lib\libQt5EventDispatcherSupport.a c:\libQT-5.10-dev\build\qtbase\lib\libQt5AccessibilitySupport.a c:\libQT-5.10-dev\build\qtbase\lib\libQt5FontDatabaseSupport.a c:\libQT-5.10-dev\build\qtbase\lib\libqtfreetype.a c:\libQT-5.10-dev\build\qtbase\lib\libQt5ThemeSupport.a -Lc:\libQT-5.10-dev\build\qtsvg\plugins\iconengines c:\libQT-5.10-dev\build\qtsvg\plugins\iconengines\libqsvgicon.a -Lc:\libQT-5.10-dev\build\qtsvg\lib -Lc:\libQT-5.10-dev\build\qtsvg\plugins\imageformats c:\libQT-5.10-dev\build\qtsvg\plugins\imageformats\libqsvg.a -Lc:\libQT-5.10-dev\build\qtimageformats\plugins\imageformats c:\libQT-5.10-dev\build\qtimageformats\plugins\imageformats\libqicns.a c:\libQT-5.10-dev\build\qtimageformats\plugins\imageformats\libqtga.a c:\libQT-5.10-dev\build\qtimageformats\plugins\imageformats\libqtiff.a c:\libQT-5.10-dev\build\qtimageformats\plugins\imageformats\libqwbmp.a c:\libQT-5.10-dev\build\qtimageformats\plugins\imageformats\libqwebp.a -Lc:\libQT-5.10-dev\build\qtbase\plugins\imageformats c:\libQT-5.10-dev\build\qtbase\plugins\imageformats\libqgif.a c:\libQT-5.10-dev\build\qtbase\plugins\imageformats\libqico.a c:\libQT-5.10-dev\build\qtbase\plugins\imageformats\libqjpeg.a -Lc:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_debugger.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_inspector.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_local.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_messages.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_native.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_nativedebugger.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_profiler.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_quickprofiler.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_server.a c:\libQT-5.10-dev\build\qtdeclarative\lib\libQt5PacketProtocol.a c:\libQT-5.10-dev\build\qtdeclarative\plugins\qmltooling\libqmldbg_tcp.a -Lc:\libQT-5.10-dev\build\qtbase\plugins\bearer c:\libQT-5.10-dev\build\qtbase\plugins\bearer\libqgenericbearer.a c:\libQT-5.10-dev\build\qtbase\plugins\bearer\libqnativewifibearer.a -Lc:\libQT-5.10-dev\build\qtdeclarative\qml\QtQuick.2 c:\libQT-5.10-dev\build\qtdeclarative\qml\QtQuick.2\libqtquick2plugin.a -Lc:\libQT-5.10-dev\build\qtdeclarative\qml\QtQuick\Layouts c:\libQT-5.10-dev\build\qtdeclarative\qml\QtQuick\Layouts\libqquicklayoutsplugin.a -Lc:\libQT-5.10-dev\build\qtvirtualkeyboard\qml\QtQuick\VirtualKeyboard\Styles c:\libQT-5.10-dev\build\qtvirtualkeyboard\qml\QtQuick\VirtualKeyboard\Styles\libqtvirtualkeyboardstylesplugin.a c:\libQT-5.10-dev\build\qtdeclarative\lib\libQt5Quick.a c:\libQT-5.10-dev\build\qtsvg\lib\libQt5Svg.a c:\libQT-5.10-dev\build\qtbase\lib\libQt5Widgets.a -luxtheme -ldwmapi c:\libQT-5.10-dev\build\qtbase\lib\libQt5Gui.a -lgdi32 -lcomdlg32 -loleaut32 -limm32 c:\libQT-5.10-dev\build\qtbase\lib\libqtlibpng.a c:\libQT-5.10-dev\build\qtbase\lib\libqtharfbuzz.a -Lc:\libQT-5.10-dev\build\qtdeclarative\qml\Qt\labs\folderlistmodel c:\libQT-5.10-dev\build\qtdeclarative\qml\Qt\labs\folderlistmodel\libqmlfolderlistmodelplugin.a c:\libQT-5.10-dev\build\qtdeclarative\lib\libQt5Qml.a c:\libQT-5.10-dev\build\qtbase\lib\libQt5Network.a -ldnsapi -liphlpapi c:\libQT-5.10-dev\build\qtbase\lib\libQt5Core.a -lmpr -lnetapi32 -luserenv -lversion -lws2_32 -lkernel32 -luser32 -lshell32 -luuid -lole32 -ladvapi32 -lwinmm -lz -lsicuin -lsicuuc c:\libICU-59.1\GCC64RT\lib\sicudt.a c:\libQT-5.10-dev\build\qtbase\lib\libqtpcre2.a
c:\libQT-5.10-dev\build\qtvirtualkeyboard\plugins\platforminputcontexts\libqtvirtualkeyboardplugin.a(plugin.o):plugin.cpp:(.text+0x589): undefined reference to `qt_static_plugin_QtQuick2WindowPlugin()'
c:\libQT-5.10-dev\build\qtvirtualkeyboard\plugins\platforminputcontexts\libqtvirtualkeyboardplugin.a(plugin.o):plugin.cpp:(.text+0x653): undefined reference to `qt_static_plugin_QtQuick2WindowPlugin()'
collect2.exe: error: ld returned 1 exit status
mingw32-make[4]: *** [Makefile.Release:68: release\basic.exe] Error 1
mingw32-make[4]: Leaving directory 'c:/libQT-5.10-dev/build/qtvirtualkeyboard/examples/virtualkeyboard/basic'
mingw32-make[3]: *** [Makefile:36: release] Error 2
mingw32-make[3]: Leaving directory 'c:/libQT-5.10-dev/build/qtvirtualkeyboard/examples/virtualkeyboard/basic'
mingw32-make[2]: *** [Makefile:41: sub-basic-make_first] Error 2
mingw32-make[2]: Leaving directory 'c:/libQT-5.10-dev/build/qtvirtualkeyboard/examples/virtualkeyboard'
mingw32-make[1]: *** [Makefile:41: sub-virtualkeyboard-make_first] Error 2
mingw32-make[1]: Leaving directory 'c:/libQT-5.10-dev/build/qtvirtualkeyboard/examples'
mingw32-make: *** [Makefile:68: sub-examples-make_first] Error 2

        cd basic\ && ( if not exist Makefile c:\libQT-5.10-dev\build\qtbase\bin\qmake.exe -o Makefile c:\libQT-5.10-dev\build\qtvirtualkeyboard\examples\virtualkeyboard\basic\basic.pro ) && "C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\bin\HostX64\x64\nmake.exe" -f Makefile

Microsoft (R) Program Maintenance Utility Version 14.11.25507.1
Copyright (C) Microsoft Corporation.  All rights reserved.

        "C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\bin\HostX64\x64\nmake.exe" -f Makefile.Release

Microsoft (R) Program Maintenance Utility Version 14.11.25507.1
Copyright (C) Microsoft Corporation.  All rights reserved.

        link /NOLOGO /DYNAMICBASE /NXCOMPAT /INCREMENTAL:NO /SUBSYSTEM:WINDOWS "/MANIFESTDEPENDENCY:type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' publicKeyToken='6595b64144ccf1df' language='*' processorArchitecture='*'" /MANIFEST:embed /OUT:release\basic.exe @C:\Users\test\AppData\Local\Temp\nmBCFE.tmp
   Creating library release\basic.lib and object release\basic.exp
qtvirtualkeyboardplugin.lib(plugin.obj) : error LNK2019: unresolved external symbol "struct QStaticPlugin const __cdecl qt_static_plugin_QtQuick2WindowPlugin(void)" (?qt_static_plugin_QtQuick2WindowPlugin@@YA?BUQStaticPlugin@@XZ) referenced in function "public: virtual class QPlatformInputContext * __cdecl QVirtualKeyboardPlugin::create(class QString const &,class QStringList const &)" (?create@QVirtualKeyboardPlugin@@UEAAPEAVQPlatformInputContext@@AEBVQString@@AEBVQStringList@@@Z)
release\basic.exe : fatal error LNK1120: 1 unresolved externals
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\bin\HostX64\x64\link.EXE"' : return code '0x460'
Stop.
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\bin\HostX64\x64\nmake.exe"' : return code '0x2'
Stop.
NMAKE : fatal error U1077: 'cd' : return code '0x2'
Stop.
NMAKE : fatal error U1077: 'cd' : return code '0x2'
Stop.
NMAKE : fatal error U1077: 'cd' : return code '0x2'
Stop.