build-system: don't build against Qt6 by default

As some Linux distros start to ship both Qt5 and Qt6, it actually makes more
sense to build only against Qt6 when the user explicitly asks for it. Having it
preferred over Qt5 seems completely wrong in hind sight.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

scripts/build.sh

@@ -96,6 +96,14 @@ while [[ $# -gt 0 ]] ; do
 			# is still available on Linux distros)
 			BUILD_WITH_WEBKIT="1"
 			;;
+		-build-with-qt6)
+			# Qt6 is not enabled by default as there are a few issues still with the port
+			# - by default the Qt6 packages don't include QtLocation, so no maps (see below)
+			# - WebKit doesn't work with Qt6, so no printing or in-app user manual
+			# - there are a few other random bugs that we still find here and there
+			# So by default we only try to build against Qt5. This overwrites that
+			BUILD_WITH_QT6="1"
+			;;
 		-build-with-map)
 			# Qt6 doesn't include QtLocation (as of Qt 6.3) - but you can build / install it from source.
 			# use this flag to force building googlemaps with Qt6
@@ -604,6 +612,9 @@ for (( i=0 ; i < ${#BUILDS[@]} ; i++ )) ; do
 	else
 		EXTRA_OPTS="-DNO_USERMANUAL=ON -DNO_PRINTING=ON"
 	fi
+	if [ "$BUILD_WITH_QT6" = "1" ] ; then
+		EXTRA_OPTS="$EXTRA_OPTS -DBUILD_WITH_QT6=ON"
+	fi
 
 	cd "$SRC"/${SRC_DIR}