Mount and unmount /dev recursively, to cope with setups where there are

interesting bind-mounts under /dev (e.g. loop devices bind-mounted by
LXD).  LP: #1716465.

debian/changelog

@@ -14,6 +14,11 @@ livecd-rootfs (2.408.15) UNRELEASED; urgency=medium
   * live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary: call apt-get
     update *before* installing packages, not after.
 
+  [ Colin Watson ]
+  * Mount and unmount /dev recursively, to cope with setups where there are
+    interesting bind-mounts under /dev (e.g. loop devices bind-mounted by
+    LXD).  LP: #1716465.
+
  -- Steve Langasek <steve.langasek@ubuntu.com>  Wed, 23 Aug 2017 17:35:40 -0700
 
 livecd-rootfs (2.408.14) xenial; urgency=medium

live-build/ubuntu-cpc/functions

@@ -82,8 +82,7 @@ mount_image() {
 setup_mountpoint() {
     local mountpoint="$1"
 
-    mount --bind /dev "$mountpoint/dev"
-    mount devpts-live -t proc "$mountpoint/dev/pts"
+    mount --rbind /dev "$mountpoint/dev"
     mount proc-live -t proc "$mountpoint/proc"
     mount sysfs-live -t sysfs "$mountpoint/sys"
     mount -t tmpfs none "$mountpoint/tmp"
@@ -136,11 +135,8 @@ umount_settle() {
 umount_partition() {
     local mountpoint=${1}
     mv resolv.conf.tmp "$mountpoint/etc/resolv.conf"
-    for submnt in var/cache/apt var/lib/apt proc sys dev/pts dev tmp;
-    do
-        umount_settle $mountpoint/$submnt
-    done
-    umount_settle $mountpoint
+    umount -R $mountpoint
+    udevadm settle
 
     if [ -n "${rootfs_dev_mapper}" -a -b "${rootfs_dev_mapper}" ]; then
         # buildd's don't have /etc/mtab symlinked

live-build/ubuntu-cpc/hooks/030-root-tarball.binary

@@ -27,6 +27,5 @@ chroot binary/boot/filesystem.dir dpkg-divert --remove --local --rename /usr/sbi
 mv resolv.conf.tmp "binary/boot/filesystem.dir/etc/resolv.conf"
 umount "binary/boot/filesystem.dir/proc"
 umount "binary/boot/filesystem.dir/sys"
-umount "binary/boot/filesystem.dir/dev/pts"
-umount "binary/boot/filesystem.dir/dev"
+umount -R "binary/boot/filesystem.dir/dev"
 umount "binary/boot/filesystem.dir/tmp"