--- a/utils/open-isns/configure.ac
+++ b/utils/open-isns/configure.ac
@@ -80,7 +80,7 @@ AC_ARG_WITH(slp,
 		else
 			WITH_SLP=yes
 			CPPFLAGS="$CPPFLAGS -I${withval}"
-			LDFLAGS="$LDFLAGS -L${withval}"
+			LDFLAGS="$LDFLAGS -L${withval} -lslp"
 		fi
 	]
 )