+URCU_LIB=
+AC_CHECK_HEADER([urcu.h], [
+ AC_CHECK_LIB(urcu, synchronize_rcu, [
+ URCU_PATH=
+ URCU_LIB="-lurcu"
+ ])
+])
+AC_ARG_WITH(urcu, [ --with-urcu path Path to userspace RCU source], [
+ AC_CHECK_FILE(["$withval/urcu.h"], [
+ URCU_PATH="$withval"
+ URCU_LIB="/liburcu.la" ],
+ AC_MSG_ERROR([Cannot find urcu.h in urcu directory]))
+])
+if test -z "${URCU_LIB}" ; then
+ AC_MSG_ERROR([Must specify urcu path.])
+fi
+AC_SUBST(URCU_PATH)
+AC_SUBST(URCU_LIB)
+