-AC_ARG_WITH(urcu, [ --with-urcu=path Path to userspace RCU library source], URCU_PATH="$withval", AC_MSG_ERROR([Must specify liburcu path.]))
-AC_CHECK_FILE("$URCU_PATH/urcu.h", , AC_MSG_ERROR([Cannot find urcu.h in liburcu directory]))
-AC_ARG_WITH(kcompat, [ --with-kcompat=path Path to libkcompat source], KCOMPAT_PATH="$withval", AC_MSG_ERROR([Must specify libkcompat path.]))
-AC_CHECK_FILE("$KCOMPAT_PATH/kcompat.h", , AC_MSG_ERROR([Cannot find kcompat.h in libkcompat directory]))
-AC_SUBST(URCU_PATH)
-AC_SUBST(KCOMPAT_PATH)