diff --git a/cmake/Modules/opm-core-prereqs.cmake b/cmake/Modules/opm-core-prereqs.cmake
index 8b3d45de1..b7cf3bf3e 100644
--- a/cmake/Modules/opm-core-prereqs.cmake
+++ b/cmake/Modules/opm-core-prereqs.cmake
@@ -5,6 +5,7 @@
 set (opm-core_CONFIG_VAR
 	HAVE_ERT
 	HAVE_SUITESPARSE_UMFPACK_H
+	HAVE_DUNE_ISTL
 	)
 
 # dependencies