Qt 5.8 MinGW developer build broken

In file included from ..\..\include/QtGui/qcolor.h:1:0,
                 from ..\..\include/QtGui/../../src/gui/image/qpixmap.h:45,
                 from ..\..\include/QtGui/qpixmap.h:1,
                 from ..\..\include\QtGui/../../src/gui/image/qbitmap.h:44,
                 from ..\..\include\QtGui/qbitmap.h:1,
                 from kernel\qt_widgets_pch.h:69:
..\..\include/QtGui/../../src/gui/painting/qcolor.h:280:8: error: 'QColor::QColor(QLatin1String)' redeclared without dllimport attribute after being referenced with dll linkage [-Werror]
 inline QColor::QColor(QLatin1String aname)
        ^
cc1plus.exe: all warnings being treated as errors
Makefile.Debug:43380: recipe for target '.pch/debug/qt_widgets_pch.h.gch/c++' failed