Index: gnucash-3.6/gnucash/register/register-gnome/CMakeLists.txt
===================================================================
--- gnucash-3.6.orig/gnucash/register/register-gnome/CMakeLists.txt
+++ gnucash-3.6/gnucash/register/register-gnome/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_subdirectory(test)
 
 #GTK before 3.14 didn't have GDK_MODIFIER_INTENT_DEFAULT_MOD_MASK
+include(CheckSymbolExists)
 check_symbol_exists(GDK_MODIFIER_INTENT_DEFAULT_MOD_MASK gdk/gdktypes.h have_mod_mask)
 if (NOT have_mod_mask)
 if (MAC_INTEGRATION)