use gtk_entry_set_activates_default() instead of redoing its work manually ourselves

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@49625 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/textctrl.h

@@ -176,6 +176,7 @@ protected:
     // set the given characteristic)
     void GTKSetEditable();
     void GTKSetVisibility();
+    void GTKSetActivatesDefault();
     void GTKSetWrapMode();
     void GTKSetJustification();