title: cross platform native open/save file dialogs
body: <p>I'm writing a UI for my program using opengl with SDL in a combination of Lua and C++</p>
  
  <p>What I need now is some library that will allow me to call a function that presents the user with a file select dialog for opening/saving a file. But if the OS offers <strong>native</strong> functionality for such a dialog, then I want to use that dialog (eg Window's GetOpenFileName).</p>
  
  <p>The only platforms I need to support are Windows and Linux, but I want to be able to still use most of the SDL &amp; openGL code I've already written.</p>
  
  <p>What options are available?</p>