Added implementation of _set_menu_sem_() to Window.cpp (should it go to a different place ?), thus fixing the build (at least here, I hope I didn't forget anything else).

Thanks to Bill Hayden for reporting and sorry again for the trouble.
Changed a comment in PopUpMenu.cpp


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@8394 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kits/interface/Window.cpp

@@ -127,6 +127,15 @@ static property_info windowPropInfo[] =
 }; 
 //------------------------------------------------------------------------------
 
+
+// TODO: Move this to a better place ?
+void
+_set_menu_sem_(BWindow *window, sem_id sem)
+{
+	window->fMenuSem = sem;
+}
+
+
 // Constructors
 //------------------------------------------------------------------------------
 BWindow::BWindow(BRect frame,