Add Window stacking support.

New windows are stacked by default.

www-client/netsurf/patches/netsurf-2.HEAD.patch

@@ -220,6 +220,69 @@ index 32860de..90cadde 100644
  	// asynchronously
  	a->Go(NULL);
  
+diff --git a/beos/scaffolding.cpp b/beos/scaffolding.cpp
+index 4003b09..3455baf 100644
+--- a/beos/scaffolding.cpp
++++ b/beos/scaffolding.cpp
+@@ -38,6 +38,9 @@
+ #include <TextControl.h>
+ #include <View.h>
+ #include <Window.h>
++#if defined(__HAIKU__)
++#include "WindowStack.h"
++#endif
+ #include <fs_attr.h>
+ extern "C" {
+ #include "content/content.h"
+@@ -571,6 +574,12 @@ NSBrowserWindow::NSBrowserWindow(BRect frame, struct beos_scaffolding *scaf)
+ 	: BWindow(frame, "NetSurf", B_DOCUMENT_WINDOW, 0),
+ 	fScaffolding(scaf)
+ {
++#if defined(__HAIKU__)
++	if (stack == NULL)
++		stack = new BWindowStack(this);
++	else
++		stack->AddWindow(this);
++#endif
+ }
+ 
+ 
+@@ -621,6 +630,8 @@ NSBrowserWindow::QuitRequested(void)
+ }
+ 
+ 
++BWindowStack* NSBrowserWindow::stack = NULL;
++
+ // #pragma mark - implementation
+ 
+ int32 nsbeos_replicant_main_thread(void *_arg)
+@@ -2407,3 +2418,4 @@ void nsbeos_scaffolding_popup_menu(nsbeos_scaffolding *g, BPoint where)
+ {
+ 	g->popup_menu->Go(where);
+ }
++
+diff --git a/beos/scaffolding.h b/beos/scaffolding.h
+index ae78391..d456c0c 100644
+--- a/beos/scaffolding.h
++++ b/beos/scaffolding.h
+@@ -29,6 +29,8 @@ extern "C" {
+ #include "desktop/plotters.h"
+ }
+ 
++class BWindowStack;
++
+ typedef struct beos_scaffolding nsbeos_scaffolding;
+ 
+ class NSBaseView : public BView {
+@@ -66,6 +68,8 @@ struct beos_scaffolding *Scaffolding() const { return fScaffolding; };
+ 
+ private:
+ 	struct beos_scaffolding *fScaffolding;
++
++	static BWindowStack* stack;
+ };
+ 
+ 
 diff --git a/beos/window.cpp b/beos/window.cpp
 index 253b5d1..b9e6491 100644
 --- a/beos/window.cpp