wrapper around the linux syscall sysinfo(2)
useful links in the wild web:
- http://man7.org/linux/man-pages/man2/sysinfo.2.html
- http://man7.org/linux/man-pages/man1/uptime.1.html
- https://github.com/capnm/golang/blob/go1.1.1/src/pkg/syscall/zsyscall_linux_amd64.go#L1050
- https://github.com/capnm/golang/blob/go1.1.1/src/pkg/syscall/ztypes_linux_amd64.go#L528
- https://github.com/capnm/golang/blob/go1.1.1/src/pkg/syscall/ztypes_linux_arm.go#L502