--- CMakeLists.txt.orig	2018-08-20 20:54:13 UTC
+++ CMakeLists.txt
@@ -27,7 +27,10 @@ dune_project()
 include(DuneMPI)
 
 #add sub_directories
-dune_add_subdirs(dune lib doc cmake/modules)
+dune_add_subdirs(dune lib cmake/modules)
+if (FREEBSD_INSTALL_DOCS)
+dune_add_subdirs(doc)
+endif()
 
 # finalize the dune project, e.g. generating config.h etc.
 finalize_dune_project(GENERATE_CONFIG_H_CMAKE)