Avoid showing the files on the ESP (i.e. a FAT formatted volume) as
executable by removing the execute permission from them.
IMO this makes the colored output of `ls` more sensible since the file
system will be mounted with `noexec` anyway.
Add a `fstype_can_fmask_dmask` function that checks if a file system
type can use the `fmask` and `dmask` mount options.
This replaces `fstype_can_umask` since it was only used in
`partition_pick_mount_options` which only cares about the file system
support for fmask & dmask now.
It somewhat reduces the coverage of the feature since there are more file
systems that support umask as opposed to those supporting dmask & dmask,
but it should not be much of an issue since fmask & dmask are supported
by vfat, exfat and ntfs3.
systemd-debug-generator(8) lists it as `systemd.debug_shell`.
According to 1d84ad9445, kernel command
line options should use an underscore instead of a dash.
This basically implements fc58c0c7bf for gshadow.
gpasswd may not have a lock/unlock that behaves the same as passwd, but
according to gshadow(5) the logic of the password field is the same.
nl6720