const syscall.SizeofIfMsghdr

2 uses

	syscall (current package)
		route_darwin.go#L16: 		return &InterfaceMessage{Header: p.Header, Data: b[SizeofIfMsghdr:any.Msglen]}
		ztypes_darwin_arm64.go#L300: 	SizeofIfMsghdr    = 0x70