fixing build issues

xs/src/slic3r/GUI/GUI.cpp

@@ -181,6 +181,8 @@ void set_main_frame(wxFrame *main_frame)
     g_wxMainFrame = main_frame;
 }
 
+wxFrame* get_main_frame() { return g_wxMainFrame; }
+
 void set_tab_panel(wxNotebook *tab_panel)
 {
     g_wxTabPanel = tab_panel;

xs/src/slic3r/GUI/GUI.hpp

@@ -97,6 +97,7 @@ void set_3DScene(_3DScene *scene);
 AppConfig*	get_app_config();
 wxApp*		get_app();
 PresetBundle* get_preset_bundle();
+wxFrame* get_main_frame();
 
 const wxColour& get_label_clr_modified();
 const wxColour& get_label_clr_sys();