hp300 bootable installcd with cd9660 support of installboot(8)

Izumi Tsutsui <[email protected]> Fri, 17 May 2024 02:59:38 +0900

Newsgroups	gmane.os.netbsd.ports.hp300,gmane.os.netbsd.devel.toolchain
Message-ID	<[email protected]>

I've posted diffs to Gnats to build hp300 bootable installcd and
add necessary changes to MI installboot(8) to handle cd9660 (ISO9660)
file system.

See netbsd-bugs@ post and gnats for details:
 https://mail-index.netbsd.org/netbsd-bugs/2024/05/16/msg083098.html
 https://gnats.netbsd.org/54455

If there is no particular objection, I'll commit the changes
this weekend.

Thanks,
---
Izumi Tsutsui