Again thanks to racoon. This is a quick fiyx, in the long term we need to
find out why this is not done automatically.
Qt5Core.dll
Qt5Gui.dll
Qt5Svg.dll
+ Qt5Widgets.dll
+ Qt5WinExtras.dll
Qt5Cored.dll (if compiling Debug version)
Qt5Guid.dll (if compiling Debug version)
Qt5Svgd.dll (if compiling Debug version)
+ Qt5Widgetsd.dll (if compiling Debug version)
+ Qt5WinExtrasd.dll (if compiling Debug version)
to C:\LyX\lyx-23-build\LYX_INSTALLED\bin
8 Define path prefix