--- CMakeLists.txt.orig	2021-08-31 14:25:00 UTC
+++ CMakeLists.txt
@@ -16,7 +16,9 @@ dune_project()
 # add subdirectories to execute CMakeLists.txt there
 add_subdirectory(bin)
 add_subdirectory(cmake)
+if (FREEBSD_INSTALL_DOCS)
 add_subdirectory(doc)
+endif()
 add_subdirectory(dune)
 add_subdirectory(lib)
 add_subdirectory(share)