--- a/gnucash/register/register-gnome/CMakeLists.txt	2020-02-02 23:11:57.704560767 +0800
+++ a/gnucash/register/register-gnome/CMakeLists.txt	2020-02-02 23:12:25.994479106 +0800
@@ -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)