There are multiple instances of setting default values for parameters in the public headers. This in turn breaks builds if QT_NO_CAST_ASCII is being used, like it seems to be default for KF5 builds when no KF5Kdelibs4Support is enabled.

Possible solution would be to avoid defining default values in those headers or wrapping them with QStringLiteral or similar.

[tpr@tuli lib]$ find . -name *.h|xargs grep "=\s*\""
./marble/AbstractDataPlugin.h:                 const QString& renderPos = "NONE", GeoSceneLayer * layer = 0 );
./marble/MapWizard.h:    static QString createLegendHtml( const QString& image = "./legend/legend.png" );
./marble/MarbleMap.h:     *    maptheme = "earth/bluemarble/bluemarble.dgml"
./marble/MarbleMap.h:     *    maptheme = "earth/bluemarble/bluemarble.dgml" 
./marble/MarbleModel.h:     *    maptheme = "earth/bluemarble/bluemarble.dgml"
./marble/MarbleModel.h:     *    maptheme = "earth/bluemarble/bluemarble.dgml"
./marble/MarbleModel.h:    void addGeoDataString( const QString& data, const QString& key = "data" );
./marble/MarbleWidget.h:     *    mapThemeId = "earth/bluemarble/bluemarble.dgml"
./marble/MarbleWidget.h:     *    maptheme = "earth/bluemarble/bluemarble.dgml"
./marble/layers/TextureLayer.h:                 const QString &renderPos = "NONE", GeoSceneLayer *layer = 0 );
./marble/layers/GeometryLayer.h:                         const QString& renderPos = "NONE", GeoSceneLayer * layer = 0 );
./marble/layers/GroundLayer.h:    const QString& renderPos = "NONE", GeoSceneLayer * layer = 0 );
./marble/layers/GroundLayer.h:    QColor m_color;  // Gets the color specified via DGML's <map bgcolor="">
./marble/layers/FogLayer.h:       const QString& renderPos = "NONE", GeoSceneLayer * layer = 0 );
./marble/layers/MarbleSplashLayer.h:                         const QString &renderPos = "SURFACE", GeoSceneLayer *layer = 0 );
./marble/layers/VectorTileLayer.h:                 const QString &renderPos = "NONE", GeoSceneLayer *layer = 0 );
./marble/layers/PlacemarkLayer.h:                 const QString &renderPos = "NONE", GeoSceneLayer *layer = 0 );
./marble/routing/RoutingLayer.h:                 const QString &renderPos = "NONE", GeoSceneLayer *layer = 0 );
./marble/AbstractFloatItem.h:                 const QString& renderPos = "FLOAT_ITEM", GeoSceneLayer * layer = 0 );

Reproducible: Always

Steps to Reproduce:
1. Include marble/MarbleModel.h to your external project
2. Compile external project with QT_NO_CAST_ASCII enabled