[REG5.14.0 beta1->beta2] Wasm: some quick/quickcontrols/quickcontrols2 examples fails to build

sed -e s/@APPNAME@/canvas/g /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/platforms/wasm_shell.html > /home/qt/RTA/qt5/Examples/Qt-5.14.0/quick/canvas/canvas.html
cp -f /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/platforms/qtloader.js /home/qt/RTA/qt5/Examples/Qt-5.14.0/quick/canvas
cp -f /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/platforms/qtlogo.svg /home/qt/RTA/qt5/Examples/Qt-5.14.0/quick/canvas
em++ -s WASM=1 -s FULL_ES2=1 -s USE_WEBGL2=1 -s NO_EXIT_RUNTIME=0 -s ERROR_ON_UNDEFINED_SYMBOLS=1 --bind -O3 -s ALLOW_MEMORY_GROWTH=1 -o canvas.js main.o canvas.js_plugin_import.o canvas.js_qml_plugin_import.o qrc_canvas.o qrc_shared.o   /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/platforms/libqwasm.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5EventDispatcherSupport.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5FontDatabaseSupport.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libqtfreetype.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5EglSupport.a /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/imageformats/libqgif.a /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/imageformats/libqicns.a /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/imageformats/libqico.a /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/imageformats/libqjpeg.a /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/imageformats/libqtga.a /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/imageformats/libqtiff.a /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/imageformats/libqwbmp.a /home/qt/RTA/qt5/5.14.0/wasm_32/plugins/imageformats/libqwebp.a /home/qt/RTA/qt5/5.14.0/wasm_32/qml/QtQuick.2/libqtquick2plugin.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5Quick.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5QmlModels.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5Qml.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5Gui.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libqtlibpng.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libqtharfbuzz.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5Network.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libQt5Core.a /home/qt/RTA/qt5/5.14.0/wasm_32/lib/libqtpcre2.a   
error: undefined symbol: _ZN7QThread12setStackSizeEj
warning: To disable errors for undefined symbols use `-s ERROR_ON_UNDEFINED_SYMBOLS=0`
Error: Aborting compilation due to previous errors
shared:ERROR: '/opt/emsdk/node-v8.9.1-linux-x64/bin/node /opt/emsdk/emscripten-1.38.27/src/compiler.js /tmp/tmpuxm2qw.txt /opt/emsdk/emscripten-1.38.27/src/embind/emval.js /opt/emsdk/emscripten-1.38.27/src/embind/embind.js /opt/emsdk/emscripten-1.38.27/src/library_pthread_stub.js' failed (1)
make: *** [Makefile:227: canvas.js] Error 1