Build failure on OpenBSD/aarch64

[vext01]

Describe the bug

I'm the package maintainer of Syncthing on OpenBSD. I'm seeing if I can get syncthing building on OpenBSD/aarch64. The syncthing build fails like this:

block$ go run build.go                                                                                                         
github.com/shirou/gopsutil/disk
# github.com/shirou/gopsutil/disk
../../go/pkg/mod/github.com/shirou/gopsutil@v3.20.10+incompatible/disk/disk_openbsd.go:81:39: undefined: sizeOfDiskstats
../../go/pkg/mod/github.com/shirou/gopsutil@v3.20.10+incompatible/disk/disk_openbsd.go:85:14: undefined: sizeOfDiskstats
../../go/pkg/mod/github.com/shirou/gopsutil@v3.20.10+incompatible/disk/disk_openbsd.go:111:34: undefined: Diskstats
../../go/pkg/mod/github.com/shirou/gopsutil@v3.20.10+incompatible/disk/disk_openbsd.go:112:9: undefined: Diskstats
exit status 2

I've been unable to trigger this by running go build in your repo, but it may be the wrong command.

To Reproduce

Clone syncthing master and run go run build.go.

Expected behavior

It should build :)

Environment (please complete the following information):

OpenBSD block.lan 6.8 GENERIC.MP#887 arm64

That's OpenBSD-current.

Additional context

go-1.15.2

Thanks :)

[Lomanic]

@vext01 Would you please run mktypes.sh (it generates Go types from Cgo definitions) on the arm64 openbsd host and open a PR with the new files so it fixes the issue for everybody? #912 (comment) also reported that (and for arm) but couldn't fix that by himself without the hardware (and so can't I for the same reason), if you have an arm (32 bit) openbsd host to do the same, this would also be greatly appreciated if you ran mktypes.sh on it and PR'd the generated files.

[Lomanic]

Fixed in #1052