openbsd build error (19)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: da1f63bfa4e8 KNF/whitespace - no code change
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=114059b9880000
kernel config: https://syzkaller.appspot.com/x/.config?x=1bc15e68cd2a49e5
dashboard link: https://syzkaller.appspot.com/bug?extid=f56c16fbd647385fd026

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f56c16...@syzkaller.appspotmail.com

sys/arch/amd64/amd64/vmm.c:900:3: error: implicit declaration of function 'x86_send_ipi' is invalid in C99 [-Werror,-Wimplicit-function-declaration]

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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.