This patch adds the symlinkat(2) and readlinkat(2) system calls which
are not exposed in golang 1.6. The implementation uses syscall.Syscall
along with syscall.SYS_SYMLINKAT and SYS_READLINKAT which are,
fortunately, available.
Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
