diff --git a/common/CMakeLists.txt b/common/CMakeLists.txt
index 59dff7b..1d9f1d6 100644
--- a/common/CMakeLists.txt
+++ b/common/CMakeLists.txt
@@ -5,6 +5,10 @@
   set(ZLIB_LIBRARIES zlib)
 endif()
 
+if(USE_INCLUDED_FLTK)
+  add_subdirectory(fltk)
+endif()
+
 add_subdirectory(os)
 add_subdirectory(rdr)
 add_subdirectory(network)