diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index a83f7cc6f5a95d943eee276e70498dab97f15f9e..76f02b3ea127b76d1b80ae855d84e3144413d0d1 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -190,8 +190,14 @@ list( APPEND cdi_unknown
   resource_unpack.h
 )
 
+option(CDI_BUILD_UNKNOWN "Build unknown sources in libcdi" ON)
+mark_as_advanced(CDI_BUILD_UNKNOWN)
+if (CDI_BUILD_UNKNOWN)
+  list(APPEND cdi_src_files ${cdi_unknown})
+endif ()
+
 add_library(cdilib
-  ${cdi_src_files} ${cdi_unknown}
+  ${cdi_src_files}
 #  INSTALL_HEADERS_LIST  cdi.h
 )