Let's hope this is last change necessary to cleanup x-* usage:
x-* persistent option, stored in utab, available for umount, etc.
X-* fstab comment only
mount(8) supports x-mount.mkdir= as well as newly recommended X-mount.mkdir=
Advantages:
* less invasive
* does not require exception for x-systemd
* does not require rename x-initrd to X-initrd
The systemd and dracut users will get the new (=fixed) functionality without a
change in fstab configuration. This is the primary goal.
Disadvantages:
* not 100% compatible libmount behavior, x-* options have not been
previously stored in utab. The API is the same, options will be still
available, but on x-* libmount will write to /run/mount/utab. For now
it seems only systemd uses x-*, and they like this behavior, so...
Addresses: https://github.com/systemd/systemd/pull/4515
Signed-off-by: Karel Zak <kzak@redhat.com>