Remove ext4+squashfs image type support
Since c1e475bf (first implemented in a637bdb8) ext4 inside squashfs + dm-snapshot for the live environment has been obsoleted by squashfs + overlayfs for the live environment.
This mode has very little, if any, use cases for archiso. The only advantage I see is that ex4 can hold ACLs, but we have EROFS for that now (with some caveats, i.e. EROFS stores change time (ctime) not modification time (mtime)). Not that we support setting custom ACLs anyway.
I propose evaluating its removal.
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Add a deprecation warning when using ext4+squashfs. -
Remove ext4+squashfs creation from mkarchiso. -
Remove dm-snapshot handling from mkinitcpio/mkinitcpio-archiso>.