[archiso] Check if /run/archiso/bootmnt is a mountpoint.

In this way allow to mount /run/archiso/bootmnt from another hook,
but still use the logic from the main mount_hook, skipping only this mount.

Signed-off-by: Gerardo Exequiel Pozzi <vmlinuz386@yahoo.com.ar>

archiso/hooks/archiso

@@ -167,7 +167,7 @@ archiso_mount_handler() {
 
     _init_loop_dev
 
-    _mnt_dev "${archisodevice}" "/run/archiso/bootmnt" "-r"
+    mountpoint -q "/run/archiso/bootmnt" || _mnt_dev "${archisodevice}" "/run/archiso/bootmnt" "-r"
 
     if [[ ! -f "${aitab}" ]]; then
         echo "ERROR: '${aitab}' file does not exist."

archiso/install/archiso

@@ -8,6 +8,7 @@ build ()
     add_binary /lib/udev/cdrom_id
     add_binary /sbin/blockdev
     add_binary /sbin/dmsetup
+    add_binary /bin/mountpoint
 
     add_file /lib/udev/rules.d/60-cdrom_id.rules
     add_file /lib/udev/rules.d/10-dm.rules