os/signal: `warning: syscall() may go away, please rewrite code to use direct calls` on openbsd

[bcmills]

#!watchflakes
post <- goos == "openbsd" && `warning: syscall\(\) may go away, please rewrite code to use direct calls`

(attn @golang/openbsd @4a6f656c; see also #36435)

[bcmills]

Looks like this was fixed by CL 484555.

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- goos == "openbsd" && `warning: syscall\(\) may go away, please rewrite code to use direct calls`

2023-04-12 15:45 openbsd-arm64-jsing go@b7428b7c os/signal.test [build] (log)

go.go(/home/gopher/build/tmp/go-link-1321096947/go.o:(syscall.libc_syscall_trampoline.abi0)): warning: syscall() may go away, please rewrite code to use direct calls

2023-04-13 17:28 openbsd-arm64-jsing go@b5a7f2ee os/signal.test [build] (log)

go.go(/home/gopher/build/tmp/go-link-1776706503/go.o:(syscall.libc_syscall_trampoline.abi0)): warning: syscall() may go away, please rewrite code to use direct calls

2023-04-13 17:46 openbsd-arm64-jsing go@74c296b6 os/signal.test [build] (log)

go.go(/home/gopher/build/tmp/go-link-2131467224/go.o:(syscall.libc_syscall_trampoline.abi0)): warning: syscall() may go away, please rewrite code to use direct calls

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- goos == "openbsd" && `warning: syscall\(\) may go away, please rewrite code to use direct calls`

2023-05-26 16:17 openbsd-arm64-jsing go@4c1d8bf5 os/signal.test [build] (log)

go.go(/home/gopher/build/tmp/go-link-2708591509/go.o:(syscall.libc_syscall_trampoline.abi0)): warning: syscall() may go away, please rewrite code to use direct calls

— watchflakes

[mknyszek]

CC @4a6f656c

This warning pops up in the last failure, but that's actually also a timeout. Maybe needs a new issue?