[Sheepdog] [PATCH] configure: add urcu into configure

[Liu Yuan]

From: Liu Yuan <tailai.ly at taobao.com>

It is suppoed to be used by sheepfs. Though sheep doesn't necessarily
need this library, its well implemented atomic operation header will
be put good use for other sheep code.

To use atomic header, just add this in the source:

#include <urcu/uatomic.h>

And its API used as uatomic_xxx().

We can get the lib dev file by
$ sudo apt-get install liburcu-dev

or compile it from the git source:
git://git.lttng.org/userspace-rcu.git

Signed-off-by: Liu Yuan <tailai.ly at taobao.com>
---
 configure.ac |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/configure.ac b/configure.ac
index 7a5eedf..cc7b6ab 100644
--- a/configure.ac
+++ b/configure.ac
@@ -77,6 +77,7 @@ AM_MISSING_PROG(AUTOM4TE, autom4te, $missing_dir)
 
 # Checks for libraries.
 AC_CHECK_LIB([socket], [socket])
+PKG_CHECK_MODULES([liburcu],[liburcu])
 
 # Checks for header files.
 AC_FUNC_ALLOCA
@@ -86,7 +87,7 @@ AC_HEADER_SYS_WAIT
 AC_CHECK_HEADERS([arpa/inet.h fcntl.h limits.h netdb.h netinet/in.h stdint.h \
 		  stdlib.h string.h sys/ioctl.h sys/param.h sys/socket.h \
 		  sys/time.h syslog.h unistd.h sys/types.h getopt.h malloc.h \
-		  sys/sockio.h utmpx.h])
+		  sys/sockio.h utmpx.h urcu.h urcu/uatomic.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
-- 
1.7.8.2