No, what's changed is that getmntent() was *not* ever used to parse /etc/fstab previously at boot time. This is not what 'mount' uses internally, so it was not part of the codepath when running 'mount -a'. It's fine that glibc has an opinion on what the format of /etc/fstab should be, but that's not a standard, and it's not what util-linux implements.
> Is it possible that glibc has changed?
No, what's changed is that getmntent() was *not* ever used to parse /etc/fstab previously at boot time. This is not what 'mount' uses internally, so it was not part of the codepath when running 'mount -a'. It's fine that glibc has an opinion on what the format of /etc/fstab should be, but that's not a standard, and it's not what util-linux implements.