warning: undefined symbol: _ZN7QThread12setStackSizeEj

Built Qt 5.14 Beta2 with Emscripten 1.38.27. 

Configured with explicitly setting -no-feature-thread option.

Now when I try to build a minimal QtQuick application, I get this error

warning: undefined symbol: _ZN7QThread12setStackSizeEj

 I tried to build with this linker options added to the .pro file:

QMAKE_LFLAGS -= "-s ERROR_ON_UNDEFINED_SYMBOLS=1"
QMAKE_LFLAGS += "-s ERROR_ON_UNDEFINED_SYMBOLS=0"

The project builds but the same error appears on the browser's console. 

It seems that in qqmlthread.cpp in QQmlThreadPrivate::QQmlThreadPrivate(QQmlThread *q) constructor , a new call setStackSize is new in this version which causes this problem on that Emscripten version.