[Qgis-developer] Building QGIS2.99 with CMAKE using Qt 5.8 and g++ 6.3 Ubuntu 16.04 64-bit

[gordon at shieldaig.com]

I get the following types of errors and have determined that the first 
is a preprocessor error due to QT_CONFIG being undefined.  Am I missing 
some kind of Qt config file?  Could someone send instructions how to 
specify please.  Is there a way to build the project using Qt Creator 
4.20?  I had a CMAKE cache file error when I tried.

Also, on Ubuntu Qt5Webkit and Qt5WebkitWidgets seem to be now 
Qt5WebEngineCore and Qt5WebEngineWidgets or perhaps something else.  
I've waited to see if anybody else would ask but they haven't as far as 
I know, how are they supposed to be handled?

Thanks.
------------------------
Sample of error messages:

` 34%] Building CXX object 
src/gui/CMakeFiles/qgis_gui.dir/raster/qgsmultibandcolorrendererwidget.cpp.o
...
/home/gordon/Qt/5.8/gcc_64/include/QtCore/qdatetime.h:256:14: error: 
missing binary operator before token "("
  #if QT_CONFIG(timezone)
...
/home/gordon/Qt/5.8/gcc_64/include/QtCore/qcoreevent.h:331:5: error: 
‘Q_ALWAYS_INLINE’ does not name a type
      Q_ALWAYS_INLINE
      ^~~~~~~~~~~~~~~
...
/home/gordon/Qt/5.8/gcc_64/include/QtCore/qmetatype.h:1625:25: error: 
‘QTypeInfoQuery’ was not declared in this scope
          enum { Flags = (QTypeInfoQuery<T>::isRelocatable ? 
QMetaType::MovableType : 0)
...
/home/gordon/Qt/5.8/gcc_64/include/QtGui/qpainter.h:490:1: error: 
‘Q_RELOCATABLE_TYPE’ was not declared in this scope
  Q_DECLARE_TYPEINFO(QPainter::PixmapFragment, Q_RELOCATABLE_TYPE);
  ^
...
/home/gordon/Qt/5.8/gcc_64/include/QtGui/qevent.h:808:5: error: 
‘Q_ALWAYS_INLINE’ does not name a type
      Q_ALWAYS_INLINE Q_DECL_CONSTEXPR bool isValid() const 
Q_DECL_NOTHROW { return m_numericId != -1; }
      ^~~~~~~~~~~~~~~
src/gui/CMakeFiles/qgis_gui.dir/build.make:1154: recipe for target 
'src/gui/CMakeFiles/qgis_gui.dir/raster/qgsmultibandcolorrendererwidget.cpp.o' 
failed
make[2]: *** 
[src/gui/CMakeFiles/qgis_gui.dir/raster/qgsmultibandcolorrendererwidget.cpp.o] 
Error 1
CMakeFiles/Makefile2:1334: recipe for target 
'src/gui/CMakeFiles/qgis_gui.dir/all' failed
make[1]: *** [src/gui/CMakeFiles/qgis_gui.dir/all] Error 2
Makefile:160: recipe for target 'all' failed
make: *** [all] Error 2`