Virtual member Fl_Window_Driver::makeWindow() now returns void

src/Fl_Window_Driver.H

@@ -141,7 +141,7 @@ public:
   virtual void make_current();
   virtual void label(const char *name, const char *mininame);
 
-  virtual Fl_X *makeWindow() { return 0; }
+  virtual void makeWindow() {}
   virtual void wait_for_expose();
   virtual void destroy_double_buffer();
   virtual void show();

src/Fl_cocoa.mm

@@ -2854,7 +2854,7 @@ void Fl_Cocoa_Window_Driver::flush()
 /*
  * go ahead, create that (sub)window
  */
-Fl_X* Fl_Cocoa_Window_Driver::makeWindow()
+void Fl_Cocoa_Window_Driver::makeWindow()
 {
   NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
   Fl_Group::current(0);
@@ -3070,7 +3070,6 @@ Fl_X* Fl_Cocoa_Window_Driver::makeWindow()
   // if (w->modal()) { Fl::modal_ = w; fl_fix_focus(); }
   if (!w->parent()) [myview did_view_resolution_change]; // to set mapped_to_retina to its current state
   [pool release];
-  return x;
 }
 
 void Fl_Cocoa_Window_Driver::fullscreen_on() {

src/Fl_win32.cxx

@@ -2006,7 +2006,7 @@ void fl_fix_focus(); // in Fl.cxx
 UINT fl_wake_msg = 0;
 int fl_disable_transient_for; // secret method of removing TRANSIENT_FOR
 
-Fl_X *Fl_WinAPI_Window_Driver::makeWindow() {
+void Fl_WinAPI_Window_Driver::makeWindow() {
   Fl_Group::current(0); // get rid of very common user bug: forgot end()
 
   fl_open_display();
@@ -2017,7 +2017,7 @@ Fl_X *Fl_WinAPI_Window_Driver::makeWindow() {
   Fl_Window *w = pWindow;
   if (w->parent() && !Fl_X::i(w->window())) {
     w->set_visible();
-    return 0L;
+    return;
   }
 
   static NameList class_name_list;
@@ -2248,8 +2248,6 @@ Fl_X *Fl_WinAPI_Window_Driver::makeWindow() {
 
   if (!im_enabled)
     flImmAssociateContextEx((HWND)x->xid, 0, 0);
-
-  return x;
 }
 
 

src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H

@@ -115,7 +115,7 @@ public:
   const Fl_Image* shape() FL_OVERRIDE;
 
   // --- window management
-  Fl_X *makeWindow() FL_OVERRIDE;
+  void makeWindow() FL_OVERRIDE;
   void take_focus() FL_OVERRIDE;
   void flush() FL_OVERRIDE;
   void flush_overlay() FL_OVERRIDE;

src/drivers/Wayland/Fl_Wayland_Window_Driver.H

@@ -98,7 +98,7 @@ public:
   const Fl_Image* shape() FL_OVERRIDE;
 
   // --- window management
-  Fl_X *makeWindow() FL_OVERRIDE;
+  void makeWindow() FL_OVERRIDE;
   void take_focus() FL_OVERRIDE;
   void flush() FL_OVERRIDE;
   void flush_overlay() FL_OVERRIDE;

src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx

@@ -1101,14 +1101,14 @@ static void process_menu_or_tooltip(struct wld_window *new_window) {
 }
 
 
-Fl_X *Fl_Wayland_Window_Driver::makeWindow()
+void Fl_Wayland_Window_Driver::makeWindow()
 {
   struct wld_window *new_window;
   Fl_Wayland_Screen_Driver::output *output;
   wait_for_expose_value = 1;
 
-  if (pWindow->parent() && !pWindow->window()) return NULL;
-  if (pWindow->parent() && !pWindow->window()->shown()) return NULL;
+  if (pWindow->parent() && !pWindow->window()) return;
+  if (pWindow->parent() && !pWindow->window()->shown()) return;
 
   new_window = (struct wld_window *)calloc(1, sizeof *new_window);
   new_window->fl_win = pWindow;
@@ -1220,7 +1220,6 @@ Fl_X *Fl_Wayland_Window_Driver::makeWindow()
   pWindow->redraw();
   // make sure each popup is mapped with its constraints before mapping next popup
   if (pWindow->menu_window()) pWindow->wait_for_expose();
-  return xp;
 }
 
 Fl_Wayland_Window_Driver::type_for_resize_window_between_screens Fl_Wayland_Window_Driver::data_for_resize_window_between_screens_ = {0, false};

src/drivers/WinAPI/Fl_WinAPI_Window_Driver.H

@@ -85,7 +85,7 @@ public:
   const Fl_Image* shape() FL_OVERRIDE;
 
   // --- window management
-  Fl_X *makeWindow() FL_OVERRIDE;
+  void makeWindow() FL_OVERRIDE;
   void size_range() FL_OVERRIDE {
     // currently nothing to do
   }

src/drivers/X11/Fl_X11_Window_Driver.H

@@ -99,7 +99,7 @@ public:
   const Fl_Image* shape() FL_OVERRIDE;
 
   // --- window management
-  Fl_X *makeWindow() FL_OVERRIDE;
+  void makeWindow() FL_OVERRIDE;
   void take_focus() FL_OVERRIDE;
   void flush_double() FL_OVERRIDE;
   void flush_overlay() FL_OVERRIDE;

src/drivers/X11/Fl_X11_Window_Driver.cxx

@@ -550,10 +550,9 @@ int Fl_X11_Window_Driver::scroll(int src_x, int src_y, int src_w, int src_h, int
   return 0;
 }
 
-Fl_X *Fl_X11_Window_Driver::makeWindow()
+void Fl_X11_Window_Driver::makeWindow()
 {
   Fl_X::make_xid(pWindow, fl_visual, fl_colormap);
-  return Fl_X::i(pWindow);
 }
 
 const Fl_Image* Fl_X11_Window_Driver::shape() {