install/56919: sysinst install in aarch64 fails -- chokes on .xz-compressed archives

[thorpej%me.com@localhost]

>Number:         56919
>Category:       install
>Synopsis:       sysinst install in aarch64 fails -- chokes on .xz-compressed archives
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jul 10 02:35:00 +0000 2022
>Originator:     Jason Thorpe
>Release:        NetBSD 9.99.98
>Organization:
RISCy Business
>Environment:
NetBSD  9.99.98 NetBSD 9.99.98 (GENERIC64) #0: Sat Jul  9 11:44:57 UTC 2022  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/evbarm/compile/GENERIC64 evbarm

[     1.000000] simplebus0 at armfdt0: SolidRun Ltd. SolidRun CEX7 Platform
>Description:
Using the sysinst installation path on evbarm-aarch64 fails when extracting the sets:

gzip: /evbarm-aarch64/binary/sets/base.tar.xz: not in gzip format

>How-To-Repeat:
Image NetBSD-9.99.98-evbarm-aarch64-install.img to a USB stick, boot the image from UEFI on a SolidRun Honeycomb LX2K.  Get pretty far down the installation path onto an NVME gumstick until this happens.
>Fix:
Probably need to build gzip with the right options.