First seed for OpenBSD/powerpc64 planted by kettenis@

In a set of commits to the tree on Saturday, Mark Kettenis (kettenis@) added the early beginnings of support for the 64-bit PowerPC platform:

Date: Sat, 16 May 2020 11:11:14 -0600 (MDT)
From: Mark Kettenis <kettenis@openbsd.org>
To: source-changes@openbsd.org
Subject: CVS: cvs.openbsd.org: src

CVSROOT:        /cvs
Module name:    src
Changes by:     kettenis@cvs.openbsd.org        2020/05/16 11:11:14

Added files:
        sys/arch/powerpc64/compile: Makefile Makefile.inc
        sys/arch/powerpc64/compile/GENERIC: Makefile
        sys/arch/powerpc64/conf: GENERIC Makefile.powerpc64
                                 files.powerpc64 ld.script
        sys/arch/powerpc64/include: _types.h atomic.h bus.h cdefs.h
                                    conf.h cpu.h db_machdep.h
                                    disklabel.h endian.h exec.h fpu.h
                                    frame.h intr.h limits.h mutex.h
                                    param.h pcb.h pmap.h proc.h psl.h
                                    ptrace.h reg.h signal.h softintr.h
                                    spinlock.h tcb.h vmparam.h
        sys/arch/powerpc64/powerpc64: autoconf.c conf.c cpu.c disksubr.c
                                      genassym.cf locore.S locore0.S
                                      machdep.c pmap.c process_machdep.c
                                      softintr.c sys_machdep.c syscall.c
                                      vm_machdep.c

Log message:
Planting the first seed for OpenBSD/powerpc64.

As support for additional hardware platforms brings opportunities to find (and fix) bugs on other, more established environments, this is definitely an interesting development. Of course it is still currently very much in its infancy, so don't drag out your POWER9 systems just yet, unless you're ready to roll up your sleeves and get some diffs submitted. Thanks to Mark for working on this port!