Building Creator on Qt 4.8.5 fails

make[3]: Betrete Verzeichnis '/home/rob/dev/bin/creator-master-4.8.5/src/plugins/qbsprojectmanager'
rm -f libQbsProjectManager.so
g++ -Wl,-z,origin '-Wl,-rpath,/home/rob/dev/bin/qt-4.8.5/lib:$ORIGIN:$ORIGIN/..:$ORIGIN/../..' -Wl,--no-undefined -Wl,-z,origin '-Wl,-rpath,$ORIGIN/../lib' -Wl,-O1 -shared -Wl,-soname,libQbsProjectManager.so -o libQbsProjectManager.so .obj/release-shared/defaultpropertyprovider.o .obj/release-shared/qbsbuildconfiguration.o .obj/release-shared/qbsbuildconfigurationwidget.o .obj/release-shared/qbsbuildstep.o .obj/release-shared/qbscleanstep.o .obj/release-shared/qbsdeployconfigurationfactory.o .obj/release-shared/qbsinstallstep.o .obj/release-shared/qbslogsink.o .obj/release-shared/qbsnodes.o .obj/release-shared/qbsparser.o .obj/release-shared/qbsproject.o .obj/release-shared/qbsprojectfile.o .obj/release-shared/qbsprojectmanager.o .obj/release-shared/qbsprojectmanagerplugin.o .obj/release-shared/qbspropertylineedit.o .obj/release-shared/qbsrunconfiguration.o .obj/release-shared/qbsstep.o .obj/release-shared/moc_defaultpropertyprovider.o .obj/release-shared/moc_propertyprovider.o .obj/release-shared/moc_qbsbuildconfiguration.o .obj/release-shared/moc_qbsbuildconfigurationwidget.o .obj/release-shared/moc_qbsbuildstep.o .obj/release-shared/moc_qbscleanstep.o .obj/release-shared/moc_qbsdeployconfigurationfactory.o .obj/release-shared/moc_qbsinstallstep.o .obj/release-shared/moc_qbslogsink.o .obj/release-shared/moc_qbsnodes.o .obj/release-shared/moc_qbsparser.o .obj/release-shared/moc_qbsproject.o .obj/release-shared/moc_qbsprojectfile.o .obj/release-shared/moc_qbsprojectmanager.o .obj/release-shared/moc_qbsprojectmanagerplugin.o .obj/release-shared/moc_qbspropertylineedit.o .obj/release-shared/moc_qbsrunconfiguration.o .obj/release-shared/moc_qbsstep.o   -L/home/rob/dev/bin/qt-4.8.5/lib -L/home/rob/dev/bin/creator-master-4.8.5/lib/qtcreator -lCore -lProjectExplorer -lCppTools -lQtSupport -lQmlJSTools -lLocator -lFind -lTextEditor -lExtensionSystem -lQtcSsh -lLanguageUtils -lCPlusPlus -lQmlJS -lUtils -lAggregation -L/home/rob/dev/bin/creator-master-4.8.5/lib/qtcreator/plugins/QtProject -L/home/rob/dev/bin/creator-master-4.8.5/src/plugins/qbsprojectmanager/../../../lib -lqbscore -lQtScript -L/home/rob/dev/bin/qt-4.8.5/lib -lQtXml -lQtGui -L/usr/X11R6/lib -lQtNetwork -lQtCore -lpthread  
/usr/bin/ld: cannot find -lqbscore
collect2: Fehler: ld gab 1 als Ende-Status zurück
make[3]: *** [../../../lib/qtcreator/plugins/QtProject/libQbsProjectManager.so] Fehler 1
make[3]: Verlasse Verzeichnis '/home/rob/dev/bin/creator-master-4.8.5/src/plugins/qbsprojectmanager'
make[2]: *** [sub-qbsprojectmanager-make_default] Fehler 2
make[2]: Verlasse Verzeichnis '/home/rob/dev/bin/creator-master-4.8.5/src/plugins'
make[1]: *** [sub-plugins-make_default-ordered] Fehler 2
make[1]: Verlasse Verzeichnis '/home/rob/dev/bin/creator-master-4.8.5/src'
make: *** [sub-src-make_default-ordered] Fehler 2