When booted using isoboot (see D14914) loader gets a bit confused because it can't work out where to boot from. This change teaches loader about ISO images and treats them as a partition format a-la GPT et al.
- rS332085: Add an ISO9660 "partition table" type to loader.
Boot an image using isoboot under BIOS and watch loader manage to find things like, y'know, the kernel.
I'm going to have to think about this. It seems like it's mixing up two different layers (filesystem and partition) in much the same way that ZFS is currently doing, but in a more annoying way.
Well an ISO image doesn't have a partition format per se. On top of that GPT doesn't have an established partition type for an ISO image. We could roll our own and plant it in there and go looking for that instead but it'd also imply that we had overlapping partition entries given that we're going to have the ESP entry pointing within the El Torito catalog and any ISO partition entry would be covering the entire disk including the GPT itself. I'm not sure whether that's going to make things complain or not.