diff --git a/sys/unix/Makefile.src b/sys/unix/Makefile.src
index e077aad23..7d5de09f0 100644
--- a/sys/unix/Makefile.src
+++ b/sys/unix/Makefile.src
@@ -670,35 +670,18 @@ objects.o:
 	$(CC) $(CFLAGS) -c -o $@ objects.c
 	@rm -f $(MAKEDEFS)
 
-# Qt 3 windowport meta-object-compiler output
+# outdated Qt 3 windowport meta-object-compiler output
 qt3_kde0.moc: ../win/Qt3/qt3_kde0.h
 	$(QTDIR)/bin/moc -o qt3kde0.moc ../win/Qt3/qt3_kde0.h
 qt3_win.moc: ../win/Qt3/qt3_win.h
 	$(QTDIR)/bin/moc -o qt3win.moc ../win/Qt3/qt3_win.h
 qt3tableview.moc: ../win/Qt3/qt3tableview.h
-	$(QTDIR)/bin/moc -o qt3tableview.moc ../win/Qt/qt3tableview.h
+	$(QTDIR)/bin/moc -o qt3tableview.moc ../win/Qt3/qt3tableview.h
 
-# Qt 4 windowport meta-object-compiler output
-qt_kde0.moc : ../win/Qt/qt_kde0.h
-	$(MOCPATH) -o qt_kde0.moc ../win/Qt/qt_kde0.h
-qt_main.moc : ../win/Qt/qt_main.h
-	$(MOCPATH) -o qt_main.moc ../win/Qt/qt_main.h
-qt_map.moc : ../win/Qt/qt_map.h
-	$(MOCPATH) -o qt_map.moc ../win/Qt/qt_map.h
-qt_menu.moc : ../win/Qt/qt_menu.h
-	$(MOCPATH) -o qt_menu.moc ../win/Qt/qt_menu.h
-qt_msg.moc : ../win/Qt/qt_msg.h
-	$(MOCPATH) -o qt_msg.moc ../win/Qt/qt_msg.h
-qt_plsel.moc : ../win/Qt/qt_plsel.h
-	$(MOCPATH) -o qt_plsel.moc ../win/Qt/qt_plsel.h
-qt_set.moc : ../win/Qt/qt_set.h
-	$(MOCPATH) -o qt_set.moc ../win/Qt/qt_set.h
-qt_stat.moc : ../win/Qt/qt_stat.h
-	$(MOCPATH) -o qt_stat.moc ../win/Qt/qt_stat.h
-qt_xcmd.moc : ../win/Qt/qt_xcmd.h
-	$(MOCPATH) -o qt_xcmd.moc ../win/Qt/qt_xcmd.h
-qt_yndlg.moc : ../win/Qt/qt_yndlg.h
-	$(MOCPATH) -o qt_yndlg.moc ../win/Qt/qt_yndlg.h
+# for Qt 5 and 6, template rules to build qt_xyz.moc from corresponding
+# ../win/Qt/qt_xyz.h are in sys/unix/hints/compiler.370 and get added
+# to src/Makefile if the appropriate hints file gets used with setup.sh;
+# so, build support for the Qt interface requires the use of hints...
 
 #	build monst.o and objects.o before executing '$(MAKE) makedefs'
 $(MAKEDEFS): $(FIRSTOBJ) \
@@ -775,7 +758,7 @@ spotless: clean
 	-rm -f ../include/nhlua.h
 	-rm -f ../include/date.h #created but no longer used, at least by core
 	-rm -f ../include/onames.h ../include/pm.h #obsolete generated files
-	-rm -f tile.c *.moc
+	-rm -f tile.c *.moc moc.qt*
 	-rm -f ../win/gnome/gn_rip.h
 
 package:
diff --git a/sys/unix/hints/include/compiler.370 b/sys/unix/hints/include/compiler.370
index e9f56d0df..3d2bf3aa1 100755
--- a/sys/unix/hints/include/compiler.370
+++ b/sys/unix/hints/include/compiler.370
@@ -114,5 +114,27 @@ endif  # clang-specific ends here
 CFLAGS+=-DGCC_WARN
 CCXXFLAGS+=-DGCC_WARN
 
+ifdef MAKEFILE_SRC
+ifdef WANT_WIN_QT
+# when switching from Qt5 to Qt6 or vice versa, any old .moc files will be
+# incompatible; get rid of them in case user hasn't run 'make spotless';
+# moc.qt5 and moc.qt6 are empty timestamp files and at most one should exist
+ifdef WANT_WIN_QT6
+# Qt 6 builds and runs (with a couple of warnings) but needs more testing
+MOCSTAMP=moc.qt6
+else
+# Qt 5 is currently the default version for nethack 3.7.x's Qt interface
+MOCSTAMP=moc.qt5
+endif
+# rule to build src/qt_foo.moc from win/Qt/qt_foo.h
+%.moc : ../win/Qt/%.h $(MOCSTAMP)
+	$(MOCPATH) -o $@ $<
+moc.qt5::
+	@if test ! -f moc.qt5; then ( rm -f *.moc moc.qt6; touch $@ ); fi;
+moc.qt6::
+	@if test ! -f moc.qt6; then ( rm -f *.moc moc.qt5; touch $@ ); fi;
+endif #WANT_WIN_QT
+endif #MAKFILE_SRC
+
 #end of compiler.370
 #------------------------------------------------------------------------------