pkg/58855: libb2 can compile intel-specific x86 binary package

[Simon Burge <simonb%NetBSD.org@localhost>]

>Number:         58855
>Category:       pkg
>Synopsis:       libb2 may compile intel-specific x86 binary package
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Nov 27 09:55:00 +0000 2024
>Originator:     Simon Burge
>Release:        NetBSD 10.99.10 (not really important)
>Organization:
Not really.
>Environment:
	System: (not really important)
	Architecture: x86_64
	Machine: amd64

>Description:
	security/libb2 builds using the -march=native compiler option.
	If built on an Intel x86, it'll include AVX512 instructions (at
	least vmovdqu8, maybe others?).  If a binary package is built on
	an Intel host and then installed on AMD host anything that tries
	to use the functions in this package will die with an illegal
	instruction error.

>How-To-Repeat:
	Build binary package of libb2 on an Intel x86, install the
	package on an AMD x86, try to run borg-backup and watch
	python die with an illegal instruction.

>Fix:
	Patch out -march=native from the libb2 build?