--- CMakeLists.txt.orig	2021-01-17 05:59:47 UTC
+++ CMakeLists.txt
@@ -24,7 +24,9 @@ dune_enable_all_packages()
 
 add_subdirectory(src)
 add_subdirectory(dune)
+if (FREEBSD_INSTALL_DOCS)
 add_subdirectory(doc)
+endif()
 add_subdirectory(lib)
 add_subdirectory(cmake/modules)
 
