pbuilder script: make arm64 case different, and add the libselinux1 needing for arm64 stuff

pbuilder/scripts/pbuilder-common

@@ -44,15 +44,22 @@ sett() {
             ;;
     esac
     case $ARCH in
-	armhf|armel|arm64)
-	    if [ "$ARCH" = "arm64" ] ; then
-		dpkg -s "qemu-system-arm" > /dev/null 2>&1 || \
-		sudo apt-get install qemu-system-arm
-	    else
-		dpkg -s "qemu-system-arm" > /dev/null 2>&1 || \
+	armhf|armel)
+	    dpkg -s "qemu-system-arm" > /dev/null 2>&1 || \
 		dpkg -s "qemu-user-static" > /dev/null 2>&1 || \
 		sudo apt-get install qemu-user-static
+	    if [ "$TYPE" = "ubuntu" ] ; then
+		MIRROR="http://ports.ubuntu.com"
 	    fi
+	    OTHER+="--debootstrap qemu-debootstrap"
+	    ;;
+	arm64)
+	    (dpkg --print-foreign-architecturs | grep arm64 > /dev/null 2>&1 && \
+		dpkg -s "libselinux1:arm64" > /dev/null 2>&1) || \
+		echo "Please enable arm64 foreign architeture in dpkg, and install \
+		libselinux1:arm64." && exit 1
+	    dpkg -s "qemu-system-arm" > /dev/null 2>&1 || \
+		sudo apt-get install qemu-system-arm
 	    if [ "$TYPE" = "ubuntu" ] ; then
 		MIRROR="http://ports.ubuntu.com"
 	    fi