[sheepdog] [PATCH] configure: exit if urcu/uatomic.h is not found

[MORITA Kazutaka]

At Sun, 20 May 2012 11:59:05 +0900,
MORITA Kazutaka wrote:
> 
> Signed-off-by: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
> ---
> 
> On my environment (debian squeeze), the package version of liburcu is
> too old (0.4.1) and I cannot compile the latest sheepdog because
> urcu/uatomic.h is missing.
> 
> Is there any way to build Sheepdog with the older version of liburcu?
> If no, we'd better check the existence of urcu/uatomic.h.
> 
> 
>  configure.ac |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)

Applied this patch since uatomic_arch.h is planed to be removed in the
longer term from liburcu.

Thanks,

Kazutaka