Now libdigikam core based on Qt6 compile and link:

...
[ 52%] Built target gui_searchwindow_obj
[ 52%] Automatic MOC for target gui_facemanagement_obj
[ 52%] Built target gui_facemanagement_obj_autogen
[ 53%] Built target gui_facemanagement_obj
[ 53%] Automatic MOC for target gui_focuspointmanagement_obj
[ 53%] Built target gui_focuspointmanagement_obj_autogen
[ 53%] Built target gui_focuspointmanagement_obj
[ 53%] Automatic MOC for target digikamcore
[ 53%] Built target digikamcore_autogen
Consolidate compiler generated dependencies of target digikamcore
[ 53%] Building CXX object core/app/CMakeFiles/digikamcore.dir/utils/digikam_version.cpp.o
[ 53%] Linking CXX shared library libdigikamcore.so
[ 53%] Built target digikamcore
[ 53%] Automatic MOC for target digikamdatabase
[ 53%] Built target digikamdatabase_autogen
...
CCBUGS: 416704