diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1b9d9114657926f8ce93ea39c636b1ec15de4fbe..a78cf5de35764c3557e2e0d0101702c84c1674c5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,6 +27,7 @@ add_subdirectory(cmake/modules)
 add_subdirectory(m4)
 add_subdirectory(dune)
 add_subdirectory(doc)
+add_subdirectory(lib)
 
 # finalize the dune project, e.g. generating config.h etc.
 finalize_dune_project(GENERATE_CONFIG_H_CMAKE)