patch 7.4.1402
Problem:    GTK 3 is not supported.
Solution:   Add GTK 3 support. (Kazunobu Kuriyama)
diff --git a/src/structs.h b/src/structs.h
index c47eef3..95b33c3 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -2736,7 +2736,9 @@
 #ifdef FEAT_GUI_GTK
     GtkWidget	*id;		    /* Manage this to enable item */
     GtkWidget	*submenu_id;	    /* If this is submenu, add children here */
+# if defined(GTK_CHECK_VERSION) && !GTK_CHECK_VERSION(3,4,0)
     GtkWidget	*tearoff_handle;
+# endif
     GtkWidget   *label;		    /* Used by "set wak=" code. */
 #endif
 #ifdef FEAT_GUI_MOTIF