Integrate zstd support into the boot loader, from earlier work by Matt Macey.
Generally happy about the cleanup and the added flexibility in the build infrastructure.
Changes to the ifdefs/if defined could use a pass to check for consistency of the comments on the closing endif.
This is normally included on the command line. I don't think we should start being inconsistent about that here.
Is this order important or can the zio_compress.h include just be pulled out of the if and avoid the else?
This seems like a weird place to do this.
It's quite unusual wrt rest of FreeBSD and the boot loader to do this for anything but the global #define options in the kernel...
Unsure. I'll try it.
Yea, I didn't want to get into the tangled mess of where it's defined, but that may be a fair bit of feedback.
Rebase and rework after comments from the OpenZFS upstreaming
to reduce diffs in upstream files. I was able to flesh out
the _STANDALONE support in the spl for FreeBSD instead of
some surgery in upstream files.