pbuilder script: add a check to make sure the right qemu user mode emulation is installed

pbuilder/scripts/pbuilder-common

@@ -45,6 +45,14 @@ 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 || \
+		dpkg -s "qemu-user-static" > /dev/null 2>&1 || \
+		sudo apt-get install qemu-user-static
+	    fi
 	    if [ "$TYPE" = "ubuntu" ] ; then
 		MIRROR="http://ports.ubuntu.com"
 	    fi