autoconf check for utimensat(2)

Unfortunately, not all distributions have utimensat(2) defined (old glibc),
so we need a way to check it in our code.

Signed-off-by: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>
created lapi/utime.h

And put there some definitions which are needed, even
if the libc doesn't provide them.

Signed-off-by: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>
safe_touch: use utimes(2) if utimensat(2) is not defined

If utimensat(2) is not defined on the platform we switch
to using utimes(2).

Signed-off-by: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>