diff --git a/config.h.cmake.in b/config.h.cmake.in
index 50fe25d..991121f 100644
--- a/config.h.cmake.in
+++ b/config.h.cmake.in
@@ -12,6 +12,7 @@
 #cmakedefine HAVE_GNUTLS_PK_ALGORITHM_T
 #cmakedefine HAVE_GNUTLS_SIGN_ALGORITHM_T
 #cmakedefine HAVE_FLTK_DEAD_KEYS
+#cmakedefine HAVE_FLTK_CLIPBOARD
 #cmakedefine ENABLE_NLS 1
 
 /* MS Visual Studio 2008 and newer doesn't know ssize_t */