From: Sergiy Vyshnevetskiy <serg@vostok.net>
Subject: [zebra 18994] Re: zebra-pj compile failure under OpenBSd 3.3
    (gmake)

properly detect rl_completion_matches vs completion_matches.
diff --git a/configure.ac b/configure.ac
index 5862455..fc854ad 100755
--- a/configure.ac
+++ b/configure.ac
@@ -216,6 +216,11 @@
            AC_MSG_ERROR([readline is too old to have readline/history.h, please update to the latest readline library.])
 	 fi
          ;;
+	 AC_CHECK_LIB(readline, rl_completion_matches)
+         if test $ac_cv_lib_readline_rl_completion_matches = no; then
+           AC_DEFINE(rl_completion_matches,completion_matches,Old readline)
+	 fi
+	 ;;
   "no" ) VTYSH="";;
   *    ) ;;
 esac